THE THOMSON ARC LAMP.

This lamp is essentially a series lamp; that is, any number of them can be put on one circuit wire, but a single lamp, used alone, burns equally well. It consists of a metal frame supporting at the bottom the holder for the globe and lower carbon, which is insulated from the frame.

The annexed figure of the plain lamp will convey an understanding of its general appearance. The upper carbon is fed downward by the mechanism contained in the box above, and is carried by a vertical round rod called the carbon holding rod.



In the regulating box of the lamp there exists a simple mechanism, the result of careful study and experiment to discover the best and simplest combination of appliances, which would obviate the necessity for the use of clockwork or dash-pots, from which fluids might be accidentally spilled, for obtaining a gradual feeding of the carbon as fast as it is consumed in producing the light, and at the same time to maintain the arc or space between the carbons in burning, of such extent as to give a steady, noiseless light, of greatest possible economy.

The lamp, once adjusted, does not require any readjustment, and, in fact, is built in such a manner as to avoid the presence of adjusting devices in it. The lamp also contains an automatic safety device for preserving the continuity of the circuit in case of accidental injury to the feeding mechanism or the carbons of the lamps. This is quite important when a considerable number of lights are operated upon one circuit wire, as a break in the circuit, due to a defective lamp, would result in the extinguishment of all the lights. With the safety device mentioned, such a break does not occur, but the flow of current is preserved through the faulty lamp.

By an exceedingly simple device upon the carbon holding rod, the lamps are extinguished when the carbons are burned out, and injury by burning the holders completely avoided.

The system is based upon the joint inventions of Elihu Thomson and Edwin J. Houston, for generators, regulators, and electric lamps, and also the patents of Elihu Thomson, in generators, regulators, and electric lamps; all of which are now operated and controlled by the Thomson-Houston Electric Co., 131 Devonshire Street, Boston, Mass.

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A MODIFICATION OF THE VIBRATING BELL.

One of the causes which gives rise to induction in the telephone lines running along the Belgian railroads is that there are so many electric bells in the stations.

Mr. Lippens proposes as a remedy for the trouble a slight modification of the vibrating bell of his invention so as to exclude from the line the extra currents from the bell.

In one of the styles (Fig. 1) a spring, R, is attached at T to a fixed metallic rod, and presses against the rod, T. The current enters through the terminal, B, traverses the bobbins, passes through T, through the spring, through T, and makes its exit through the other terminal. The armature is attracted, and the point, P, fixed thereto draws back the spring from the rod, T, and interrupts the current; but, at the moment at which the point touches the spring, and before the latter has been detached from the rod, T, the electro-magnet becomes included in a short circuit, and the line current, instead of passing through the bobbins for a very short time, passes through the wire, T, the armature, and the rod, T, so that the extra current is no longer sent into the line.



In another style (Fig. 2) the current is not interrupted at all, but enters through the terminal, B, traverses the bobbins, and goes through C to the terminal, B.



As soon as the armature is attracted, the spring, R, which is fixed to it presses against the fixed metallic rod, T, and thus gives the electricity a shorter travel than it would take by preference. The current ceases, then, to pass through the bobbins, demagnetization occurs, and the spring that holds the armature separates anew. The current now passes for a second time into the bobbins and produces a new action, and so on. There is no longer, then, any interruption of the current, and the motions of the hammer are brought about by the change in direction of the current, which alternately traverses and leaves the bobbins.

In a communication that he has addressed to us on the subject of these bells, Mr. Lippens adds a few details in regard to the mode of applying the ground pile to micro-telephone stations.

Being given any two stations, he puts into the ground at the first a copper plate, and at the second a zinc one, and connects the two by a line wire provided with two vibrating bells and two telephone apparatus. The earth current suffices to actuate the bells, but, in order to effect a call, the inventor is obliged to run them continuously and to interrupt them at the moment at which he wishes to communicate. The correspondent is then notified through the cessation of noise in the bells, and the two call-apparatus are thrown out of the circuit by the play of the commutator, and are replaced by the micro-telephone apparatus.

It is certainly impracticable to allow vibrating bells to ring continuously in this manner. The ground pile would, at the most, be only admissible in cases where the call, having to be made from only one of the stations, might be effected by a closing of the circuit.—La Lumiere Electrique.

* * * * *

The advantage of lighting vessels by electricity was shown when the steamer Carolina, of the old Bay Line between Baltimore and Norfolk, ran into the British steamship Riversdale in a dense fog off Cedar Point, on Chesapeake Bay. The electric lights of the Carolina were extinguished only in the damaged part of the boat, and her officers think that if she had been lighted in any other way, a conflagration would have followed the collision.

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PHOTO PLATES—WET AND DRY.

Dr. Eder has recently published, in the Correspondenz, the first of a series of articles embodying the results of his more recent work on gelatino bromide; and we now reproduce the substance of the article in a somewhat abstracted form.

The "sensitiveness of a wet" plate continues to be used as a rough and ready standard of comparison; and, notwithstanding the fact that it is physically impossible to exactly compare the sensitiveness of a wet plate with that of a gelatino bromide film, it is convenient to refer to wet plates as some kind of a rough standard.

Experiments have shown that a gelatine plate which gives the number 10 on the Warnerke sensitometer, may be regarded as approximately corresponding to the average wet plate; and setting out from this point, the following table has been constructed:

Sensitometer Sensitiveness, expressed in terms number. of a "Wet Plate."

10 1 11 1-1/3 12 1-3/4 13 2-1/3 14 3 15 4 16 5 17 7 18 9 19 12 20 16 21 21 22 27 23 36 24 48 25 63

The nature of the developer used has, of course, some influence on the sensitiveness of the plates; but in the above cases it is assumed that oxalate developer, without any addition, is used; or pyro., to which ammonia is added at intervals of about thirty seconds, so as to produce a slight tendency to fog; the time of development being from three to four minutes. The numbers are supposed to be read after fixation, the plate being held against the sky.

Schumann's statement that a gelatino bromide plate is less sensitive when developed at 30 deg. C. than when developed at 5 deg., is contested; the more recent investigations of Dr. Eder serving to demonstrate that a developer at a moderate high temperature acts very much more rapidly than when the temperature is low; but when a sufficient time is allowed for each developer to thoroughly penetrate the film, the difference becomes less apparent. Here are examples:

A.—Oxalate Developer.

Temperature of developer 4-8 deg. C. 16-17 deg. C. 26-28 deg. C. Time of development 1 min. 3 deg. W. 8 deg. W. 13 deg. W. " " 2 min. 91/2 deg. W. 10 deg. W. 15 deg. W.

B.—Pyrogallic Developer.

Temperature of developer 1-2 deg. C. 26-28 deg. C. Time of development 1/4 min. 6 deg. W. 10 deg. W. " " 3 min. 14 deg. W. 15 deg. W.

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INTENSIFIER FOR WET PLATES.

By MAJOR WATERHOUSE.

The collodion process is still preferred for reproducing black and white designs, drawings, engravings, etc., where very dense negatives are desirable. The fixed and washed plate is put in a bath of bromide of copper (ten per cent. solution); the film whitens immediately, and when the color is even all over, the plate is taken out and plunged into a bath of the ordinary ferrous oxalate developer. It takes a dark olive tint, which is very non-actinic, the shadows meanwhile remaining very clear.—Photo. News.

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GELATINO BROMIDE EMULSION WITH BROMIDE OF ZINC.

By this time of the year I have no doubt many, both amateur and professional photographers, are either contemplating or are actually at work making their stock of plates for the coming season, and it is to be hoped that we shall have more favorable weather than we had last year.

Some four or five years since I tried using bromide of zinc instead of the ordinary salts, namely, bromide of ammonium or potassium. I only made one batch of plates at the time, which possessed several important features I considered an advantage, and I think well worth while following out. I do not think it can be denied that ordinary gelatine plates, if exposed in a weak light, fall very short of the results obtained with wet collodion when compared side by side, gelatine being almost useless under these conditions, and there is a decided gain in the result in this respect if the emulsion be made with zinc bromide.

In using bromide of zinc there is a slight difficulty to overcome, but it can be overcome, as I have succeeded in making a perfect emulsion. It will, I have no doubt, be remembered that Mr. L. Warnerke was the first to call attention to this salt in the days of collodion emulsion; and I think he claimed for an emulsion prepared with it that the image would stand more forcing without fogging to gain any amount of intensity. This was said of a collodion emulsion, and I also find that it is the same when used in a gelatine emulsion. I have heard a great many say, when speaking about the intensity of gelatine plates, that they can get any amount of intensity. I grant that in a studio where the operator has full command over the lighting of his subject by means of blinds, but it is not so in the field, especially when the light is dull. I have seen thousands of negatives, and as a rule I have found want of intensity has been the fault, and generally through the light. Now if we can find a remedy for this, it will be a step in advance.

What I claim for bromide of zinc is that a rapid plate can be made with it, and any degree of intensity can be readily obtained with a very small proportion of pyrogallic acid in the developer. The cry as always is to use plenty of pyrogallic acid and you can get any amount of intensity. I remember, in the early days of gelatine, as much as six grains being recommended, and I have myself, under extraordinary circumstances, used as much as ten grains to the ounce; but I think it is now, to a certain extent, a thing of the past. With the plates to which I refer, I found that I only required to use for a 71/2 x 5 plate one grain of pyrogallic acid in about three ounces of developer to get full density without the slightest difficulty. If the ordinary quantity were used far too much density was obtained, and the plate ruined beyond recovery; but with so small a quantity of pyro. the plate was not so much stained as with a larger quantity, and the negative took far less time to develop on account of the intensity being so readily obtained.

In making a gelatine emulsion with zinc it must be decidedly acid or it fogs. I prefer nitric acid for the purpose. I also found that some samples of the bromide behaved in a very peculiar way. All went on well until it came to the washing, when the bromide of silver washed out slowly, rendering the washing water slightly milky; this continued until the whole of the bromide of silver was discharged from the gelatine, and the latter rendered perfectly transparent as in the first instance. I remember a gentleman mentioning at one of the meetings of the South London Photographic Society that he was troubled in the same way as I was at that time. I think if a few experiments were made in this direction with the zinc salt and worked out, it would be a great advantage.—Wm. Brooks, in Br. Jour. of Photo.

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DESIGN FOR A VILLA.

The villa of which we give a perspective drawing is intended as a country residence, being designed in a quiet and picturesque style of domestic Gothic, frequently met with in old country houses. It is proposed to face the external walls with red Suffolk bricks and Corsham Down stone dressings, the chimneys to be finished with moulded bricks. The attic gables, etc., would be half-timbered in oak, and the roof covered with red Fareham tiles laid on felt. Internally, the hall and corridors are to be laid with tiles; the wood finishing on ground floor to be of walnut, and on first floor of pitch pine. The ground floor contains drawing-room, 23 ft. by 16 ft., with octagonal recess in angle (which also forms a feature in the elevation), and door leading to conservatory. The morning-room, 16 ft. by 16 ft., also leads into conservatory. Dining-room, 20 ft. by 16 ft., with serving door leading from kitchen. The hall and principal staircase are conveniently situated in the main part of the house, with doors leading to the several rooms, and entrances to garden. The domestic offices, though conveniently placed, are entirely cut off from the main portion of the house by a door leading from the hall. In the basement there is ample cellar accommodation for wine or other purposes. The first floor contains four bed-rooms, two dressing-rooms, bath-room, w.c., etc. The attic floor, reached by the servants' staircase, contains two servants' bed-rooms, day and night nurseries, and box and store rooms. The estimated cost is L3,800. The design is by Mr. Charles C. Bradley, of 82 Wellesley Road, Croydon.—Building Times.



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WILLIAM SPOTTISWOODE.

William Spottiswoode, President of the Royal Society, was born in London, Jan. 11, 1825. He belongs to an ancient Scottish family, many members of which have risen to distinction in Scotland and also in the New World.

In 1845 he took a first class in mathematics, and he afterward won the junior (1846) and the senior (1847) university mathematical scholarships. He returned to Oxford for a term or two, and gave a course of lectures in Balliol College on Geometry of Three Dimensions—a favorite subject of his. He was examiner in the mathematical schools in 1857-58. On leaving Oxford, he immediately, we believe, took an active part in the working management of the business of the Queen's printers, about this time resigned to him by his father, Andrew Spottiswoode, brother of the Laird of Spottiswoode. The business has largely developed under his hands.

Other subjects than mathematics have occupied his attention: at an early age he studied languages, as well Oriental as European.



As treasurer and president, he has been continuously on the Council of the Royal Society for a great many years, and through his exceptional gifts as an administrator he has rendered it invaluable services. He has rendered similar services to the British Association, to the London Mathematical Society, and to the Royal Institution. We have permission to make the following extract from a letter written by a friend of many years' standing: "In the councils (of the various societies) he has always been distinguished by his sound judgment and his deep sympathy with their purest and highest aims. There never was a trace of partisanship in his action, or of narrowness in his sympathies. On the contrary, every one engaged in thoroughly scientific work has felt that he had a warm supporter in Spottiswoode, on whose opportune aid he might surely count. The same breadth of sympathy and generosity of sentiment has marked also his relations to those more entirely dependent upon him. The workmen in his large establishment all feel that they have in him a true and trustworthy friend. He has always identified himself with their educational and social well-being." We give here a list of some of the offices Mr. Spottiswoode has held, and of the honors that have been bestowed upon him: Treasurer of the British Association from 1861 to 1874, of the Royal Institution from 1865 to 1873, and of the Royal Society from 1871 to 1878. In 1871 he succeeded Dr. Bence Jones as Honorary Secretary to the Royal Institution. President of Section A, 1865; of the British Association, 1878; of the London Mathematical Society, 1870 to 1872; of the Royal Society, 1879, which office he still holds. Correspondent of the Institut (Academie des Sciences), March 27, 1876. He is also LL.D. of the Universities of Cambridge, Dublin, and Edinburgh, D.C.L. of Oxford, and F.R.A.S., F.R.G.S., F.R.S.E. In addition to these honors he has many other literary and scientific distinctions.—Nature.

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ACETATE OF LIME.

I have made a series of experiments with regard to finding a reliable method of estimating the acetic acid in commercial acetate of lime, and find the following gives the best results: The sample is finely ground and about 6 grms. weighed into a half-liter flask, dissolved in water, and diluted to the containing mark. 100 c.c. of this solution are distilled with 70 grms. of strong phosphoric acid nearly to dryness, and 50 c.c. of water are added to the residue in the retort and distilled till the distillate gives no precipitate with nitrate of silver, titrate the distillates with standard caustic soda, evaporate to dryness in a platinum dish, and ignite the residue before the blow pipe, which converts the phosphate of soda (formed by a little phosphoric acid carried over in the distillation) into the insoluble pyrophosphate and the acetate of soda into NaHO; dissolve in water, and titrate with standard H{2}SO{4}, which gives the amount of soda combined with the acetic acid in the original sample. In a number of samples analyzed they were found to vary hardly anything.—C. H. Slaytor, in Chem. News.

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THE REMOVAL OF AMMONIA FROM CRUDE GAS.

In connection with the many plans now brought forward to utilize the ammonia in the gases escaping from coke ovens and blast furnaces, it may be of interest to refer to a process brought out some years ago in connection with illuminating gas manufacture by Messrs. Bolton & Wanklyn, and adapted by them, we understand, to the metallurgical branches also.

When bone ash or any other substance containing phosphate of lime is treated with sulphuric acid, the products formed are superphosphate of lime and hydrated sulphate of lime; this mixture is known as superphosphate of lime, in commerce, and is the substance used in this process. This substance is capable of absorbing carbonic acid and ammonia from foul gas. The complete action can only take place in the presence of a certain proportion of carbonic acid, so that the process is not so successful with "well-scrubbed illuminating gas." The superphosphate is converted into carbonate of lime, while the ammonia combines with the phosphoric acid to form phosphate of ammonia; the hydrated sulphate of lime is also acted upon, and forms carbonate of lime and sulphate of ammonia; so that, presuming the action to be complete, and the material to be thoroughly saturated with carbonic acid and ammonia from the foul gas, the result is a mixture of carbonate of lime and phosphate and sulphate of ammonia.

Under these circumstances, the mixture absorbs one equivalent of carbonic acid for every four equivalents of ammonia; therefore, if the superphosphate process be substituted for the ordinary washers and scrubbers, a large proportion of the carbonic acid and also the whole of the sulphureted hydrogen is left in the gas, and must be dealt with in other ways.

This superphosphate process has been at work at the South Metropolitan Gas Works, Old Kent Road, for nearly two years. In practice it is usual to water the superphosphate before use with ammoniacal liquor, and it is used in dry purifiers, in layers about eight inches thick.

This process has been thoroughly investigated at the Munich Gas Works, by Drs. Bunte and Schilling, and the report made by these gentlemen proves its practical efficiency, and therefore the question of its advantage, as compared with washing and scrubbing, is based chiefly upon financial considerations. It is evident that in foreign parts, or in any place where there is a difficulty in disposing of the ammonia, the obtaining of the same in a dry form offers several advantages as compared with having it as a weak solution.

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RECONVERSION OF NITRO-GLYCERIN INTO GLYCERIN.

By C.L. BLOXAM.

The following experiments on this subject appear to possess some interest at the present moment:

1. Nitro-glycerin was shaken with methylated alcohol, which dissolves it readily, and the solution was mixed with an alcoholic solution of KHS (prepared by dissolving KHO in methylated spirit, and saturating with H_{2}S gas). Considerable rise of temperature took place, the liquid became red, a large quantity of sulphur separated, and the nitro-glycerin was entirely decomposed.

2. Nitro-glycerin was shaken with a strong aqueous solution of commercial K_{2}S. The same changes were observed as in 1, but the rise of temperature was not so great, and the liquid became opaque very suddenly when the decomposition of the nitro-glycerin was completed.

3. The ordinary yellow solution of ammonium sulphide used in the laboratory had the same effect as the K{2}S. In this case the mixture was evaporated to dryness on the steam bath, when bubbles of gas were evolved, due to the decomposition of the ammonium nitrite. The pasty mass of sulphur was treated with alcohol, which extracted the glycerin, subsequently recovered by evaporation. Another portion of the mixture of nitro-glycerin with ammonium sulphide was treated with excess of PbCO{3} and a little lead acetate, filtered, and the ammonium nitrite detected in the solution. These qualitative results would be expressed by the equation—

C3H5(NO)+3NH4HS = C3H5(OH)3 + 3NH4NO2 + S3,

which is similar to that for the action of potassium hydrosulphide upon gun-cotton.

4. Flowers of sulphur and slaked lime were boiled with water, till a bright orange solution was obtained. This was filtered, and some nitro-glycerin powered into it. The reduction took place much more slowly than in the other cases, and more agitation was required, because the nitro-glycerin became coated with sulphur. In a few minutes, the reduction appearing to be complete, the separated sulphur was filtered off. The filtrate was clear, and the sulphur bore hammering without the slightest indication of nitro-glycerin.

This would be the cheapest method of decomposing nitro-glycerin. Perhaps the calcium sulphide of tank-waste, obtainable from the alkali works, might answer the purpose.—Chemical News.

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CARBONIC ACID AND BISULPHIDE OF CARBON.[1]

[Footnote 1: A paper read before the Royal Society, April 5, 1883.]

By JOHN TYNDALL, F.R.S.

Chemists are ever on the alert to notice analogies and resemblances in the atomic structure of different bodies. They long ago indicated points of resemblance between bisulphide of carbon and carbonic acid. In the case of the latter we have one atom of carbon united to two of oxygen, and in the case of the former one atom of carbon united to two of sulphur. Attempts have been made to push the analogy still further by the discovery of a compound of carbon and sulphur analogous to carbonic oxide, but hitherto, I believe, without success. I have now to note a resemblance of some interest to the physicist, and of a more settled character than any hitherto observed.

When, by means of an electric current, a metal is volatilized and subjected to spectrum analysis, the "reversal" of the bright band of the incandescent vapor is commonly observed. This is known to be due to the absorption of the rays emitted by the vapor by the partially cooled envelope of its own substance which surrounds it. The effect is the same in kind as the absorption by cold carbonic acid of the heat emitted by a carbonic oxide flame. For most sources of radiation carbonic acid is one of the most transparent of gases; for the radiation from the hot carbonic acid produced in the carbonic oxide flame it is the most opaque of all.

Again, for all ordinary sources of radiant heat, bisulphide of carbon, both in the liquid and vaporous form, is one of the most diathermanous bodies ever known. I thought it worth while to try whether a body reputed to be analogous to carbonic acid, and so pervious to most kinds of heat, would show any change of deportment when presented to the radiation from hot carbonic acid. Does the analogy between the two substances extend to the vibrating periods of their atoms? If it does, then the bisulphide, like the carbonic acid, will abandon its usually transparent character, and play the part of an opaque body when presented to the radiation from the carbonic oxide flame. This proved to be the case. Of the radiation from hydrogen, a thin layer of bisulphide transmits 90 per cent., absorbing only 10. For the radiation from carbonic acid, the same layer of bisulphide transmits only 25 per cent., 75 per cent. being absorbed. For this source of rays, indeed, the bisulphide transcends, as an absorbent, many substances which, for all other sources, far transcend it.

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THE HAIR, ITS USE AND ITS CARE.[1]

[Footnote 1: Abstract of a paper read before the Pennsylvania State Medical Society, at Norristown, May 10, 1883.—N.Y. Med. Jour.]

By JOHN V. SHOEMAKER, A.M., M.D., Physician to the Philadelphia Hospital for Skin Diseases.

The object of this paper is to briefly describe the hair and its important functions, and to suggest the proper manner of preserving it in a healthy state.

I know full well that much has been written upon this useful part of the human economy, but the constant increase of bald heads and beardless faces, notwithstanding all our modern advancement in the application of remedies to the cure of disease, prompts me to point out to you the many ways of retaining, without medication, the hair, which is a defense, ornamentation, and adornment to the human body.

[Dr. Shoemaker here gave an interesting history of the growth and development of the hair and its uses, which we are compelled to omit. Then, proceeding, he said:] Now, the hair, which fulfills such an important function in the adornment and health of the body, requires both constitutional and local care to keep it in its normal, healthy state. When I say constitutional care, I mean that the various organs of the body that assist in nourishing and sustaining the hair-forming apparatus should, by judicious diet, exercise, and attention to the nervous system, be kept healthy and sound, in order that they in turn may assist in preserving the hairs in a vigorous condition.

In the first place, that essential material, food, which is necessary to supply the waste and repair of all animal life, should be selected, given, or used according to good judgment and experience.

Thus, mothers should feed their infants at regular intervals according to their age, and not permit them to constantly pull at the breast or the bottle until the little stomach becomes gorged with food, and some alimentary disorder supervenes, often setting up a rash and interfering with the growth and development of the hair. It is likewise important, in case the baby must be artificially fed, to select good nutritious food as near as possible like the mother's—cow's milk, properly prepared, being the only recognized substitute. Care and discretion should likewise be taken by parents and nurses, after the infant has developed into childhood, to give simple, substantial, and varied food at regular periods of the day, and not in such quantities as to overload the stomach. Children need active nutrition to develop them into robust and healthy men and women; and it is from neglect of these important laws of health, and in allowing improper food, that very often bring their results in scald head, ring-worm, and scrofula, that leave their stamp in the poor development of the hair. With the advent of youth and the advance of years, food should be selected and partaken of according to the judgment and experience of its acceptable and wholesome action on the consumer.

The meals should also be taken at regular intervals. At least four hours should be left between them for the act of digestion and the proper rest of the stomach.

It is, on the contrary, when the voice of nature has been stifled, when judgment and experience have been set aside, that mischief follows; when the stomach is teased and fretted with overloading, and the food gulped down without being masticated, gastric and intestinal derangement supervenes, which is one of the most prolific sources of the early decay and fall of the hair.

The nervous system, which is one of the most important portions of the human structure, and which controls circulation, secretion, and nutrition, often by being impaired, plays a prominent part in the production of baldness. Thus, it has been demonstrated by modern investigation that the nerves of nutrition, by their defective action, are often the cause of thinning and loss of hair. The nutritive action of a part is known to suddenly fail, the hair-forming apparatus ceases to act, the skin changes from a peculiar healthy hue to a white and shining appearance, and often loses at the same time its sensibility; the hairs drop out until very few remain, or the part becomes entirely bald. It is the overtaxing of the physical powers, excessive brain work, the exacting demands made by parents and teachers upon children's mental faculties, the loss of sleep, incessant cares, anxiety, grief, excitement, the sudden depression and exaltation of spirits, irregular and hastily bolted meals, the lack of rest and recreation, the abuse of tobacco, spirits, tea, coffee, and drugs of all forms, that are fruitful sources of this defective action of the nerves of nutrition, and consequent general thinning and loss of hair.

The hair, particularly of the head, should also receive marked local attention. In reference to the use of coverings for it, I know of no better rules than those which I laid down in my chapter on clothing in "Household Practice of Medicine" (vol. i., p. 218, William Wood & Co., New York), in which I state that the head is the only part of the body so protected by nature as to need no artificial covering.

The stiff hats so extensively worn by men produce more or less injury. Premature baldness most frequently first attacks that part of the head where pressure is made by the hat. It is, indeed, a pity that custom has so rigidly decreed that men and women must not appear out of doors with heads uncovered. It would be far better for the hair if to be bare-headed were the rule, and to wear a hat the exception.

Since we can not change our social regulations in this respect, we should endeavor to render them as harmless as possible.

The forms of hats that are least injurious are: for Winter, soft hats of light weight, having an open structure, or pierced with numerous holes; for Summer, light straws, also of open structure.

As regards the head-covering of women, the fashions have been for several years favorable to proper form. The bonnet and hat have become quite small, and cover but little of the head. This beneficial condition, however, is in part counterbalanced by the weight of false curls, switches, puffs, etc., by the aid of which women dress the head. These, by interfering with evaporation of the secretions, prevent proper regulations of the temperature of the scalp, and likewise lead to the retention of a certain amount of excrementitious matter, both of which are prolific sources of rapid thinning and loss of hair in women.

False hair has likewise sometimes been the means of introducing parasites, which give rise to obstinate affections of the scalp.

Cleanliness of the entire surface of the skin should next demand attention, and that should be done by using water as the medium of ablution. It is a well-known physiological law that it is necessary, in order to enable the skin to carry on its healthful action, to have washed off with water the constant cast of scales which become mingled with the unctuous and saline products, together with particles of dirt which coat over the pores, and thus interfere with the development of the hairs. Water for ablution can be of any temperature that may be acceptable and agreeable, according to the custom and condition of the bather's health. Many chemical substances can be combined with water to cleanse these effete productions from the skin. Soap is the most efficacious of all for cleanliness, health, and the avoidance of disease. Soap combines better with water to render these unctuous products miscible, and readily removes them thoroughly from the skin. The best variety of soap to use is the pure white soap, which cannot be so easily adulterated by coloring material, or disguised by some perfume or medicinal substance. Ablution with soap and water should be performed once or twice a week at least, particularly to the head and beard, in order to keep open the hair tubes so that they may take in oxygen, give out carbon, carry on their nutrition, and maintain the hairs in a fine, polished, and healthy condition. In using water to the scalp and beard, care should be taken not to use soap-water too frequently, as it often causes irritation of the glands, and leads to the formation of scurf. It is equally important to avoid using on the head, the daily shower-bath, which, by its sudden, rapid, and heavy fall, excites local irritation, and, as a result, loss of hair quickly follows. In case the health demands the shower-bath, the hair should be protected by a bathing cap. The most acceptable time to wash the hair, to those not accustomed to doing it with their morning bath, is just before retiring, in order to avoid going into the open air or getting into a draught and taking cold. After washing, the hair should be briskly rubbed with rough towels, the Turkish towel heated being particularly serviceable. Those who are delicate or sick, and fear taking cold or being chilled from the wet or damp hairs, should rub into the scalp a little bay rum, alcohol, or oil, a short time after the parts have been well chafed with towels. The oil is particularly serviceable at this period, as it is better absorbed, and at the same time overcomes any dryness of the skin which often follows washing.

It might be well to add in this connection that I have frequently been consulted, by those taking salt-water baths, as to the care of the hair during and after the bath. If the bather is in good health, and the hair is normal, the bather can go into the surf and remain at least fifteen minutes, and on coming out should rub the hair thoroughly dry with towels.

Ladies should permit it remain loose while doing so, after which it can be advantageously dressed.

It is, however, often injurious to both men and women having some wasting of the hair to go into the surf without properly protecting the head; the sea water has not, as is often thought, a tonic action on the scalp; on the contrary, it often excites irritation and general thinning. Again, it is most decidedly injurious to the hair for persons to remain in the surf one or two hours, the hair wet, and the head unprotected from the rays of the sun. This latter class of bathers, and those who hurriedly dress the hair wet, which soon becomes mouldy and emits a disagreeable odor, are frequent sufferers from general loss and thinning of the hair.

An agreeable and efficient adjunct after ablution, which I have already referred to, is oil. Oil has not only a cleansing action upon the scalp, but it also overcomes any rough or uneven state of the hair, and gives it a soft and glossy appearance.

The oil of ergot is particularly serviceable in fulfilling these indications, and, at the same time, by its soothing and slight astringent action upon the glands, will arrest the formation of scurf. In using oil, the animal and vegetable oils should always be preferred, as mineral oils, especially the petroleum products, have a very poor affinity for animal tissues.

Pomatum is largely used by many in place of oil, as it remains on the surface and gives a full appearance to the hairs, thus hiding, sometimes, the thinness of the hair.

It will do no harm or no special good if it contains pure grease, wax, harmless perfume, and coloring matter, but it is often highly adulterated, or, the fat in it decomposing, sets up irritation on the part to which it is applied. I therefore always advise against its use.

The comb and brush are also agents of the toilet by which the hair is kept clean, vigorous, and healthy. The comb should be of flexible gum, with large, broad, blunt, round, and coarse teeth, having plenty of elasticity. It should be used to remove from the hairs any scurf or dirt that may have become entangled in them, to separate the hairs and prevent them from becoming matted and twisted together.

The fine-tooth comb, made with the teeth much closer together, can be used in place of the regular toilet comb just named when the hair is filled with very fine particles of scurf, dirt, or when parasites and their eggs infest the hairs. It should, however, always be borne in mind that combs are only for the hair, and not for the scalp or the skin, which is too often torn and dug up by carelessly and roughly pulling these valuable and important articles of toilet through the skin as well as the hair.

The brush with moderately stiff whalebone bristles may be passed gently over the hair several times during the day, to brush out the dust and the dandruff, and to keep the hair smooth, soft, and clean; rough and hard brushing the hair with brushes having very stiff bristles in them, especially the metal or wire bristles, is of no service, but often irritates the parts and causes the hair to fall out. [Dr. Shoemaker then denounced the use of the so-called electric brush, saying its use was injurious, as also was the effort to remove dandruff by the aid of the comb and brush. Continuing, he remarked:] And now the question arises, Should the hair be periodically cut? It may be that cutting and shaving may for the time increase the action of the growth, but it has no permanent effect either upon the hair-bulb or the hair sac, and will not in any way add to the life of the hair.

On the contrary, cutting and shaving will cause the hair to grow longer for the time being, but in the end will inevitably shorten its term of life by exhausting the nutritive action of the hair-forming apparatus. When the hairs are frequently cut, they will usually become coarser, often losing the beautiful gloss of the fine and delicate hairs. The pigment will likewise change—brown, for instance, becoming chestnut, and black changing to a dark brown. In addition, the ends of very many will be split and ragged, presenting a brush like appearance. If the hairs appear stunted in their growth upon portions of the scalp or beard, or gray hairs crop up here and there, the method of clipping off the ends of the short hairs, of plucking out the ragged, withered, and gray hairs, will allow them to grow stronger, longer, and thicker.

Mothers, in rearing their children, should not cut their hair at certain periods of the year (during the superstitious time of full moon), in order to increase its length and luxuriance as they bloom into womanhood, and manhood. This habit of cutting the hair of children brings evil in place of good, and is also condemned by the distinguished worker in this department, Professor Kaposi, of Vienna, who states that it is well known that the hair of women who possess luxuriant locks from the time of girlhood never again attains its original length after having once been cut.

Pincus has made the same observation by frequent experiment, and he adds that there is a general opinion that frequent cutting of the hair increases its length; but the effect is different from that generally supposed. Thus, upon one occasion he states that he cut off circles of hair an inch in diameter on the heads of healthy men, and from week to week compared the intensity of growth of the shorn place with the rest of the hair. The result was surprising to this close and careful observer, as he found in some cases the numbers were equal, but generally the growth became slower after cutting, and he has never observed an increase in rapidity.

I might also add that I believe many beardless faces and bald heads in middle and advancing age are often due to constant cutting and shaving in early life. The young girls and boys seen daily upon our streets with their closely cropped heads, and the young men with their clean-shaven faces, are, year by year, by this fashion, having their hair-forming apparatus overstrained.

I also must condemn the modern practice of curling and crimping, the use of bandoline, powders, and all varieties of gum solutions, sharp hair-pins, long-pointed metal ornaments and hair combs, the wearing of chignons, false plaits, curls, and frizzes, as the latter are liable to cause headaches and tend to congestion. Likewise I protest against the use of castor-oil and the various mixtures extolled as the best hair-tonics, restoratives, vegetable hair-dyes, or depilatories, as they are highly injurious instead of beneficial, the majority of hair-dyes being largely composed of lead salts. But, should your patients wish to hide their gray hairs, probably the best hair-dye that can be used safely is pyrogallic acid or walnut juice, the hairs being first washed with an alkaline solution to get rid of the grease. Nitrate of silver is also a good and safe hair-dye, but its application should be done by one experienced in its use. The judicious use of these hair-dyes will give the hair above the surface of the skin a brownish-black appearance, the intensity of the color of which depends upon the strength of the solution. But hair-dyeing for premature grayness should be avoided, as the diseased condition may be averted by the proper remedies. Never permit the hair to be bleached for the purpose of obtaining the fashionable golden hue, as the arsenical solution generally used is highly dangerous; but, if your patients must have their hair of a golden color, insist upon their hairdresser using the peroxide of hydrogen, which is less dangerous than the preparation first mentioned.

Perhaps one of the most pernicious compounds used for the hair at the present day is that which is sold in the shops as a depilatory. It is usually a mixture of quicklime and arsenic, and is wrongly used and recommended at this time by many physicians to remove hairy moles and an excessive growth of hair upon ladies' faces. Its application excites inflammation of the skin; and, while it removes the hair from the surface for a time, it often leaves a scar, or makes the part rough, congested, and deformed.

In the meantime, the hair will grow after a short period stronger, coarser, and changed in color, which will even more disfigure the person's countenance. With the present scientific knowledge of the application of electrolysis, hairs can be removed from the face of ladies or children, or in any improper situation, in the most harmless manner without using such obnoxious and injurious compounds as depilatories.

In conclusion, let me add that, if the hair becomes altered in texture, or falls out gradually or suddenly, or changes in color, a disease of the hair, either locally or generally, has set in, and the hair, and perhaps the constitution, now needs, as in any other disease, the constant care of the physician.

A general remedy for this or that hair disease that may develop will not answer, as hair diseases, like other affections, have no one remedy which will overcome wasting, thinning, or loss of color. Patients reasoning upon this belief, frequently apply to me for a remedy to restore their hair to its full vigor or give them back its color. I always reply that I have no such remedy.

The general health, as well as the scalp and hairs, must be examined carefully, particularly the latter, with the lens and microscope. All changes must be watched, and the treatment varied from time to time according to the indications.

No one remedy can, therefore, under any circumstances, suit, as the remedy used to-day may be changed at the next or succeeding visit. No remedy for the hair will be necessary if the foregoing advice be followed which I have just narrated, and which is the result of some seven years of labor and experience.

The proper consideration and putting into practice of these suggestions will most certainly secure to the rising generation fewer bald heads and more luxuriant hair than is possessed at the present day.

* * * * *

[Concluded from SUPPLEMENT No. 387, page 6179.]



THE INFLUENCE OF EFFECTIVE BREATHING IN DELAYING THE PHYSICAL CHANGES INCIDENT TO THE DECLINE OF LIFE, AND IN THE PREVENTION OF PNEUMONIA, CONSUMPTION, AND DISEASES OF WOMEN.

By DAVID WARK, M.D., 9 East 12th Street, New York.

PNEUMONIA.

During the past winter inflammation of the lungs has destroyed the lives of many persons who, although they were in most cases past the meridian of life, yet still apparently enjoyed vigorous health, and, I have little doubt, would still have been alive and well had the preventive means here laid down against the occurrence of the disease from which they perished been effectively practiced at the proper time.

The most important anatomical change occurring during the progress of pneumonia is the solidification of a larger or smaller part of one or both lungs by the deposit in the terminal bronchial tubes and in the air cells of a substance by which the spongy lungs are rendered as solid and heavy as a piece of liver. The access of the respired air to the solidified part being totally prevented, life is inevitably destroyed if a sufficiently large portion of the lungs be invaded.

This deposit succeeds the first or congestive stage, and it occurs with great rapidity; an entire lobe of the lung may be rendered perfectly solid by the exudation from the blood of fully two pounds of solid matter in the short space of twelve hours or even less. The rapidity with which the lungs become solidified amply accounts for the promptly fatal results that often attend attacks of acute pneumonia. If recovery takes place, the foreign matter by which the lung tissue has been solidified is perfectly absorbed and the diseased portion is found to be quite uninjured. The only natural method by which the blood can be freed from the presence of foreign matter is by the oxidation—the burning—of such impure matters; the results being carbonic acid gas that escapes by the lungs and certain materials that are eliminated chiefly by the kidneys. But when these blood impurities exist in the vital fluid in unusually large quantities, or if the respiratory capacity be inadequate, the natural internal crematory operations are a partial failure. But nature will not tolerate the presence of such impurities in the vital fluid; if they cannot be eliminated by natural means they must by unnatural means; therefore such material is very frequently deposited in various parts of the body, the point of deposit being often determined by some local disturbance or irritation.

For instance, if a person whose blood is in fairly good condition takes a cold that settles on his lungs, he either recovers of it spontaneously or is readily cured by means of some cough mixture; but if his blood be loaded with tubercular matter, the latter is extremely liable to be deposited in his lungs; the cough that was excited in the first place by a simple cold becomes worse and persistent, in a few months his lungs show signs of disorganization, and he has consumption of the acute or chronic type, as the case may be.

On the other hand, if the impure matter by which the blood is loaded be of the kind that causes the pulmonary solidifications of pneumonia, the latter disease is very likely to be developed if a cold on the lungs be caught.

The liability of any individual to attacks of acute pneumonia is therefore determined very largely by the presence or absence in his blood of the matter already alluded to. If his blood be free from it, no cold, however severe, is competent to originate the disease.

There can be no question but that good living and sedentary habits have a strong tendency to befoul the blood; the former renders effective respiration all the more necessary for the removal from the blood of whatever nutritive matter has been taken beyond the needs of the system, and the latter inevitably diminishes the respiratory motions to the lowest point consistent with physical comfort. From these conditions originates the active predisposing cause of pneumonia, to which we have already alluded.

The disease is more fatal in the very young and in the aged; the mortality seems to bear a direct ratio to the respiratory capacity; in young subjects the breathing powers have not been fully developed like the other physical capacities, while in the old the respiratory volume has been diminished by the stiffening of the chest walls and of the lungs by the senile changes already detailed.

There can be no question but that protection from cold and judicious attention to the health generally, by suitable exercise and diet, has a powerful tendency to prevent that overloaded condition of the blood to which I believe acute pneumonia to be chiefly due; still I have no doubt but that the most active preventive measure that can be adopted is keeping up the respiratory capacity to the full requirements of the system, a precaution which is specially necessary to ease-loving and high-living gentlemen who are past the prime of life. I am of the opinion that if such persons would cultivate their breathing powers by the simple means here recommended, their liability to pneumonia would be notably reduced.

THE TRUE FIRST STAGE OF CONSUMPTION.

The progress of tubercular consumption has been divided by pathologists into three stages. The first stage being that in which a deposit of tubercular matter occurs in the lung tissue, the second is entered on when the tubercles soften, and the third when they have melted down, been expectorated, and cavities have formed. But the real beginning of this most insidious and justly dreaded disease not infrequently antedates for a long time, often for several years, the deposit of any tubercular matter. During all this time an expert examiner can detect the slight but very significant changes already taking place in the pulmonary organs. Physicians determine the condition of the lungs chiefly through the sounds elicited by percussion of the chest walls by the end of the middle finger, or a small rubber hammer adapted to the purpose, and by those produced by the respired air rushing in to and out of the bronchial tubes and air vesicles. The percussion sounds yielded by the chest during what has been aptly called the pre-tubercular stage do not differ from those elicited in health, because it is only when some morbid matter exists in the lungs that the percussion note is altered, therefore negative results only are obtained in the real first stage by this mode of examination. But important information can be obtained by interrogating the sounds due to the inspired air rushing into and distending the air vesicles. When the lungs are perfectly healthy, these are breezy and almost musical. During the pre-tubercular stage they become drier and harsher; qualities of evil omen that continue to increase as time passes, if properly directed means be not adopted to correct the evil; but so far none of the symptoms that indicate the slightest deposit of tubercle can be detected, but the breathing capacity of such persons is never up to the full requirements of the system. The reader is referred to the table already given, which exhibits the decline of the breathing capacity of persons suffering from consumption in its several stages. When the disease has made such decided progress that tubercles are already deposited in the lungs in sufficient quantity to give rise to the physical signs by which their presence is proved, this carefully compiled table shows that the diminution of the vital capacity already amounts to one-third of that considered by Dr. Hutchinson to be necessary to the maintenance of health.

During the pre-tubercular stage the breathing capacity rarely falls so much as 33 per cent. below the healthy standard, but it is never up to the normal vital volume. This fact is most significant, especially when it occurs in an individual whose relatives have succumbed to this disease; but it rarely attracts sufficient attention from such persons as to induce them to have their breathing capacity measured, much less to take effective measures to bring and keep it up to the healthy standard. So long as there are, to them, no tangible symptoms of approaching mischief, and they feel fairly well, they act as if they thought "that all men were mortal but themselves." Yet it is from among persons who have an inherited but latent tendency to tubercular disease, and whose lung power is below par, that the great army of consumptives who die every year is recruited. It is very difficult to induce persons who ought to be interested in this matter to take effective measures for their future safety when the terrible symptoms accompanying the last stages of the disease often fail to shake the sufferer's confident expectation of recovery; and we sometimes see them engaged in laying plans for the future when death is imminent. I regret deeply to be obliged to make these statements, because I am convinced that if the suggestions laid down in this work were generally reduced to practice by those who have reason to dread the development of tubercular disease, many valuable lives would be saved.

THE DEVELOPMENT OF TUBERCULAR MATTER IN THE BLOOD.

During the digestive processes the starchy, saccharine, and albuminoid elements of food are dissolved, and the fatty matters are emulsified. A uniform milky solution is thus formed, which is rapidly absorbed into the general circulation; some of it passes directly through the walls of the vessels into the blood, and some is taken up by the lacteals and reaches the vital fluid by traversing the complicated series of tubes known as the absorbent system, and the numerous glands connected with it. The chief function of the starchy and fatty food elements is to keep up the physical temperature, by being submitted to oxidation in the organism; therefore it is not necessary that they should experience any vitalizing change, but are fitted to discharge their duties in the vital domain by simply undergoing the solution that fits them for absorption. But the materials intended to enter into the composition of the body must be developed into living blood, in order to be fitted to become part and parcel of the organs by which power is evolved, and through the use of which we see, hear, feel, think, and move. This wonderful process begins and is carried forward in the absorbent system, which has been described by Dr. Carpenter as a great blood-making gland. But the vital transformation is not completed until the nutritive materials have been submitted to the action of the liver, and afterward to the influence of oxygen in the capillaries of the lungs. The food that was eaten a few hours before is thus converted into rich scarlet arterial blood, if every part of the complex vitalizing processes has been properly conducted. But the influence of oxygen is requisite, not only to complete the vitalization of the embryo blood in the lungs, it is an absolutely essential element in every step of the vitalizing process in the absorbents.

The average quantity of food required to sustain an ordinary man in health and strength, I have previously stated, is about two pounds avoirdupois daily, and an equal weight of oxygen is necessary to the integrity of the vitalizing processes undergone by the food, and to maintain the physical temperature. When the requisite supply of oxygen is reduced, the extrication of heat within the system is promptly diminished, but the vitalization of digested food is unfavorably affected much more slowly, but with equal certainty. If the quota of oxygen existing in the arterial blood of the vessels whose duty it is to supply the vital fluid to the absorbent system, be inadequate to enable these operations to go on properly, the life-giving processes must necessarily be imperfectly accomplished. Under these circumstances the digested material is imperfectly vitalized, and is therefore inadequately fitted to be used in building up and repairing the living body. But its course in the system cannot be delayed, much less stopped.

The blood possesses a definite constitution, which cannot be materially altered without the rapid development of grave, perhaps fatal consequences. The nutritive matters received into the blood must be given up by it to the tissues for their repair, whether such materials are well or ill fitted for the vital purposes. Dr. B.W. Carpenter, of London, the celebrated physiologist, makes the following pertinent statements on this subject, which I condense from his great work on physiology: "We frequently find an imperfectly organizable product, known by the designation of tubercular matter, taking the place of the normal elements of tissue, both in the ordinary process of nutrition, and still more when inflammation is set up.

From the examination of the blood of tuberculous subjects it appears that, although the bulk of the coagulum obtained by stirring or beating is usually greater than that of healthy blood, yet this coagulum is not composed or well elaborated fibriae, for it is soft and loose, and contains an unusually large number of colorless blood corpuscles, while the red corpuscles form an abnormally small proportion of it. We can understand, therefore, that such a constant deficiency in capacity for organization must unfavorably affect the ordinary nutritive processes; and that there will be a liability to the deposit of imperfectly vitalized matter, instead of the normal elements of tissue, even without any inflammation. Such appears to be the history of the formation of tubercles in the lungs and other organs.

When it occurs as a kind of metamorphosis of the ordinary nutritive processes and in this manner, it may proceed insidiously for a long period, so that a large part of the tissue of the lungs shall be replaced by tubercular deposit without any other sign than an increasing difficulty of respiration." These views are strongly corroborated by the following facts:

In making post mortem examinations of persons who have died of consumption, tubercles of different kinds are found in the same subject; some of these, having been deposited during what is called the first stage of the disease before the breathing powers were much impaired, bear evident traces of organization in the form of cells and fibers more or less obvious, these being sometimes almost as perfectly formed as living matter, at least on the superficial part of the deposit, which is in immediate contact with the living structures around.

This variety of tubercle has a tendency to contract and remain in the lungs without doing much injury. But as the disease progressed, and the breathing capacity progressively diminished, tubercular matter occurs, evincing less and less organization, showing a tendency to break down and cause inflammation in the surrounding lung tissue, until at last we find crude yellow tubercles that have become softened, and formed cavities almost as soon as they were deposited.

Some cases of chronic consumption pass in a few months through the various stages from the deposit of the first tubercle to a fatal termination.

The progress of the disease is determined largely by the nature of the tubercular matter at the time it is deposited.

The variety of matter which has been partially vitalized commonly exists in small quantity, has a strong tendency to maintain its semi-organized condition unchanged by time, and rarely causes inflammation.

A small or moderate quantity of this sort of tubercle exists in the lungs of many persons, in whom it produces no tangible symptoms, and who are therefore quite unconscious of its presence; and even when it does exist in sufficient quantity to develop the symptoms of lung disorder, the progress of the disease is slow, often continuing for many years. It constitutes a variety of consumption which is specially amenable to proper treatment. On the other hand, the soft, yellow, cheesy, tubercular matter, which is totally destitute of any vitality, is too often deposited in large quantities, acts on the adjacent lung tissue as an active irritant, causes inflammation, undergoes softening, forms cavities, defies treatment, and rapidly hurries the sufferers to a premature grave. These facts, taken in connection with the immunity from lung diseases enjoyed by those whose respiratory capacity is well developed and properly used, as well as the beneficial effects that are promptly secured in the favorable varieties of consumption by any important increase in the vital volume, I believe fully justify the statement that tubercles are the results of defective nutrition directly traceable to inadequate respiratory capacity, either congenital or acquired—in other words, tubercles are composed of particles of food which have failed to acquire sufficient life while undergoing the vital processes, because the person in whom they occur habitually breathed too little fresh air.

Persons who possess what is called the scrofulous constitution are specially liable to the occurrence of tubercular matter when their respiration is defective, or they are exposed to any other influences that favor its development in the organism. But habitually defective respiration, or the breathing of an atmosphere containing too little oxygen, which practically amounts to the same thing, has a very powerful tendency in the same direction, in persons who are apparently as free from scrofulous taint as any human being can be.

THE VALUE OF COD-LIVER OIL IN THE PREVENTION OF CONSUMPTION.

There is a broad but not commonly recognized distinction between what constitutes a medicine and a food. All the materials that normally enter into the composition of the living body, and are necessary to the maintenance of health and strength, may be property classed as foods, whether they be obtained from the animal, vegetable, or mineral kingdoms; thus the iron, sulphur, phosphorus, lime, potash, etc., required by the system usually exist in and are organically combined with the various foods in common use, and they are perhaps quite as essential to the physical well-being as albuminoid, fatty, and saccharine matters. When the system is suffering from lack of any of the above mentioned chemicals, their administration is to be regarded as the giving of nutritive substances, although they be prescribed by a physician in divided doses and procured from a pharmacist.

On the other hand, a medicine is any substance that does not naturally enter into the composition of the body, but which has the power, when skillfully used, to modify the physical processes so that physiological disorder—disease, shall be replaced by physiological harmony—health. Belladonna, hyoscyamus, opium, etc., are familiar examples of medicaments. Therefore a food is any substance that is capable of directly contributing to the nutrition of the body, and medicine is a substance competent, under proper conditions, to secure the same results indirectly. Viewed in the light of the above definition, cod-liver oil is to be regarded as a very valuable food, as well as a most effective remedy both for the prevention and cure of consumption.

I have previously stated that food is divided by physiologists into three great classes. The albuminoids are used to build up the organism, while the fatty and saccharine are burned in the body to keep it warm. Although these are the chief functions devolving on the above mentioned food elements, yet they are mutually interdependent on each other for the proper performance of their several offices. Thus the albuminoids cannot undergo the wonderful vitalizing process necessary to fit them to enter into and form part of the living body, except an adequate quantity of fatty matter be present to assist in the vital transformation. On the other hand, the assistance of the albuminoids is equally necessary to enable the fatty and saccharine foods to maintain the internal heat of the body. Of all fatty matters, whether derived from the animal or vegetable kingdom, none possesses the property of stimulating and perfecting the nutritive processes in so high a degree as cod-liver oil; it is more readily emulsified and fitted for absorption by the pancreatic secretion during intestinal digestion than any other fatty matter of which we have any knowledge. The beneficial effects of its use have been proved in myriads of cases of confirmed consumption, and if it were used for prolonged periods by persons who are losing weight, and whose breathing capacity is too little, along with effective cultivation of the latter function, many persons would escape this disease who now succumb to it.

THE INFLUENCE OF NORMAL BREATHING ON THE FEMALE GENERATIVE ORGANS.



The body is divided into three separate stories by two partitions. The diaphragm, A, separates the cavity of the chest from that of the abdomen. The partition, D, forms a floor for the digestive cavity, F, and a roof for the pelvis; the pelvic cavity is occupied mainly by the generative organs. The upper part of the uterus is firmly fixed to the partition, D, by which the pelvis is covered. Now, the diaphragm, A, and the external respiratory muscles are in ceaseless motion performing the act of breathing. The diaphragm acts like the piston of a pump, both on the lungs above, and on the contents of the abdominal and pelvic cavities below. When it rises from B to A, it diminishes the size of the thoracic cavity, compresses the lungs, and assists in the expiratory part of breathing; at the same time it acts through the contents of the abdominal cavity on the pelvic roof, D, to which the uterus is attached, and raises it from D to C. When the diaphragm contracts, it descends from A to B, increases the size of the thoracic cavity, inflates the lungs, promotes the inspiratory part of breathing, pushes the walls of the chest and abdomen outward from F to E, and lowers the pelvic roof at the same time the uterus sinks from C to D. When the effect of these respiratory motions is not diminished by muscular debility, rigidity of the thoracic walls, or by unsuitable clothing, they have so direct an effect on the pelvic contents that the uterus and its appendages make two distinct motions every time a woman breathes. When the diaphragm rises and the breath is expelled, the womb is elevated from one inch to one inch and a half, because the roof of the pelvis, to which it is attached, is lifted about this distance, because of gentle suction from above. The uterus and its appendages are thus kept in constant motion, up and down, chiefly by action of the muscles by which breathing is carried on.

Several influences combine to maintain the circulation of the blood. The pumping action of the heart and the affinity of the blood for the walls of the capillary vessels require to be assisted by the motion both of the body as a whole and of its parts in order to keep the circulation flowing equably through every tissue. Therefore muscular action and the resulting bodily motion play a very important part in maintaining the general and local blood circulation. During the contraction of a muscle, the blood current flowing through it is, for the time being, retarded, but when relaxation occurs the blood flows into its vessels more freely than if no momentary cessation had taken place. When the body or any of its parts is deprived of motion, the blood circulation stagnates, and the nutrition, general or local, as the case may be, promptly becomes impaired. This is specially true of the uterus. Gentle but constant motion is absolutely essential to keep up a healthy uterine blood circulation. Nature has provided for the automatic performance of all the ceaseless internal motions that are necessary to the continuance of life and the preservation of health; thus the heart beats, the respiratory muscles act, the stomach executes a churning motion during gastric digestion, the intestines pass on their contents by worm-like contractions, automatically without our supervision and without causing fatigue, being under the control of the sympathetic system of nerves chiefly. It is equally true, but not so well recognized, that the previously described motions that are committed to the pelvic organs from the respiratory apparatus are absolutely necessary to the continued health of the uterus and its appendages. But the womb is not under the control of the voluntary muscles, therefore it cannot be directly moved by them, nor are its necessary motions influenced by the sympathetic system of nerves as are the heart, stomach, and intestines, etc., but it is fortunately under the indirect but positive control of involuntary muscles that never, as long as breathing continues, cease their work. Nature has thus made ample provision to keep the uterus in automatic motion. As before stated, the natural ceaseless heavings of the lungs, chest, and diaphragm, aided by the muscles inclosing the abdomen, have the duty assigned them of communicating automatic motion to the uterus and the other contents of the pelvis. When the diaphragm descends from A to B, and the lungs are filled with air, the uterus sinks in the pelvic cavity in obedience to the downward pressure from above, as before stated; the circulation through the uterus is then for a moment retarded, but the next instant, when the lungs are emptied of air and the diaphragm rises, the blood flows forward more freely than if it had not been momentarily obstructed. Ample provision has thus been made to maintain a healthy circulation through the uterus.

The uterine motions I have described are fully adequate for the purposes indicated. But when the natural stimulus of motion is withheld, the circulation becomes sluggish causing congestion, which may develop into inflammation. Under these conditions the uterus gradually becomes displaced, falling backward, forward or downward as the case may be. The blood vessels by which the uterus is supplied thus have their caliber diminished by bending; the circulation through them is retarded just as the flow of water in a rubber tube is obstructed by a kink. A very good idea of what occurs in the uterus under the conditions just described may be obtained by winding a string around the fingers.

As the coats of the arteries are thick, and the pressure exerted by the ligature has less power to prevent the arterial blood flowing outward past the string to the end of the finger than it has to prevent the return of the venous blood toward the heart, therefore the part beyond the ligature soon becomes congested, the blood stagnating in the capillaries. If the ligature be sufficiently tight and kept on long enough, mortification will take place, but if the circulation be only moderately obstructed, the congestion will continue until ulceration occurs. A similar condition is developed in the uterus when the necessary natural stimulus of motion fails to be communicated to it or when it is so far out of its proper place that the circulation through it is obstructed.

I believe the above described condition to be a most potent but inadequately recognized cause of the various forms of uterine diseases that distress so many women.

SHOWING HOW THE BREATHING POWERS MAY BE DEVELOPED.

When the circumference of the chest bears a due proportion to the size of the body generally; when its walls and the lungs possess a suitable degree of elasticity; when the strength of the respiratory muscles is adequate to their work, and no undue opposition is offered to the breathing motions by the clothing—then the vital volume is always up to the full requirements of the system. But when one or all of these are lacking in any important degree, the breathing capacity is proportionately diminished. If the testimony of the spirometer be corroborated by the impaired physical condition of the individual, its correction should be sought in part at least by enlarging the chest, increasing the elasticity of its walls and of the lungs, and by augmenting the strength of the respiratory muscles. These results may commonly be secured by diligent and persevering use of the following exercises:



A trapeze, Fig. 2, should be suspended from the ceiling, so that the bar shall be six inches above the head of the person who is to use it; the toes should be placed under straps nailed to the floor to keep them in position. Then if the bar be grasped and the body thrown forward, the trapeze, the arms, and the body will form the segment of a circle.

The exercise is taken by causing the body to describe a complete circle in the manner indicated in the cut. Little muscular effort is required if the motion be rapid, because the momentum is sufficient to carry the body around; but if the rotation be slow, more exertion is required. This movement is specially adapted to the breathing powers of weak persons, yet the most vigorous can readily get from it all the exercise their chest and lungs require.

By means of these exercises the chest is gently but effectively expanded in every direction and the elasticity of its walls promoted, the air cells are expanded, and the lungs are rendered more permeable to the respired air, and the strength of the respiratory muscles is developed.



Fig. 3 illustrates an exercise for the chest that is taken without any apparatus other than an ordinary doorway. The exerciser should stand in the position indicated in the engraving, and then step forward with each foot alternately as far as possible without stretching the chest too severely. The longer the step the more vigorous the exercise will be.



Fig. 4 shows an exercise taken between two chairs; the position indicated in the cut having been assumed, the chest is then slowly lowered and raised three to six times. This exercise is adapted to strong persons only.

THE EFFECTS OF ADEQUATE RESPIRATION IN SPECIAL CASES.

When the nutrition of the body is promoted by effective respiration, and waste matters are promptly removed, the chances that tubercle will be developed in persons who are predisposed thereto are reduced to a minimum.

Better materials are furnished by the nutritive processes to renew the tissues, so that the occurrence of those degenerations that result in various fatal affections, peculiar to the decline of life, are rendered much less probable or are prevented altogether, and the chances that death shall take place by old age is increased. The system possesses much greater resisting power against the influence of malaria and the poisons that give rise to typhoid fever, scarlatina, diphtheria, measles, etc.

When the motions of a woman's respiratory organs are normal and are properly communicated to the pelvic organs, she enjoys the greatest possible immunity attainable against the development of any diseases peculiar to the sex.

* * * * *



VITAL DISCOVERIES IN OBSTRUCTED AIR AND VENTILATION.[1]

[Footnote 1: Read by Wm. C. Conant before the Polytechnic Association of the American Institute, New York, May 10, 1883.]

I suppose that we all consider ourselves to be sufficiently impressed with the importance of ventilation. If I should stop here to declaim against foul exhalations, or to dwell upon the virtues of fresh air, you might feel inclined to interrupt me by saying, "Oh, we know all about that! If you have anything practical to advance, come to the point." Gentlemen, I beg your pardon, but I must say that the great fact concerning ventilation, as yet, is that its strongest advocates are not conscious of one-half the seriousness of the subject; and the second fact is that the supposed means of ventilation prescribed by science fail to secure it.

This, then, is my point to-night—the supreme necessity, still urgent, and universally urgent, for a reformation of the breath of life. I believe in a promised time when the days of a man's life shall again be as the days of a tree. And next to the abolition of vice and sin, I believe that the very grandest factor of such result must be an entire disuse of obstructed air for the lungs. I propose to bring forward some evidence of the necessity, and likewise of the possibility, of a reform so radical and sweeping as this. The subject is too wide for the occasion. I shall be able to read only extracts from what I have prepared, in the few minutes that you can give with patience to my unpracticed lecturing.

The best prescription that doctors have to give (when we are not too far gone to take it) is to live out of doors. Why is this? Why is life out of doors proverbially synonymous with robust health? Why is it that a superior vitality, and a singular exemption from disease, notoriously distinguish dwellers in the open air, by land or sea? Without disparaging the virtues of exercise or of bracing temperature, indispensable as these are for the recuperation of enfeebled constitutions, we must admit that among the native and settled inhabitants of the open air high health is the rule in warm climates as well as in cold, and with the very laziest mortals that bask in the sun, or loaf in the woods. The fact is that simple vegetative health seems to be nearly independent of all other external conditions but that of a pure natural diet for the lungs. Man in nature seems to thrive as spontaneously as plants, by the free grace of air, earth, and sun. On the other hand, the very diseases from which houses are supposed to defend us—that most numerous class resulting from colds—are the special scourge of the lives that are most carefully shielded from their commonly supposed cause—exposure to the open air. Those diseases diminish, and entirely disappear, just so far as exposure in the pure and freely moving air becomes complete and habitual. Soldiers, inured to camp life, catch cold if they once sleep in a house; and, generally speaking, the inhabitants of the free air contract colds only by exposure to confined exhalations from their own or other bodies, within the walls of houses. The explanation of this is plain and simple: Carbonic acid detained within four walls accumulates in place of the breath of life—oxygen—and narcotizes the excretory function of the skin. The moment that this great and continual vent of waste and impurity from the system is obstructed, internal derangement ensues in every direction. All hands, so to speak, are strained to extra duty to discharge the noxious accumulation. The lungs labor to discharge the load thrown back upon them, with hastened respiration, increased combustion, and feverish heat. The pores of the mucous membrane in the nose, throat, alimentary canal, or bronchial passages, are forced by an aggravated discharge (or catarrh), and this congestive and inflammatory pressure is a fever also. There is nothing of "cold" about it except as an auxiliary and antecedent, in cases where an external chill has struck upon nerves already half paralyzed by the universal narcotic—carbonic acid—which house dwellers may be said to "smoke" perpetually.

So much for nerve-poison; but blood-poisoning is a still more terrible characteristic of house-protected existence. It is now the almost universal opinion of the medical profession that the whole class of malarial and zymotic diseases that make such frightful progress and havoc in the most civilized communities, are due to living germs with which the exhalations of organic waste and decay are everywhere loaded in inconceivable numbers. They are known to multiply themselves many times over, every two or three hours. They swarm into the blood by millions, through all the absorbents, especially those of the lungs, that drink the atmosphere in which they are suffered to linger and propagate. Mr. Dancer, the eminent microscopist, counted in a sample from such an atmosphere a number of organized germs equivalent to 3,700,000 in the volume of air hourly inhaled by one person. That is over 60,000 germs per minute, and about 2,000 in every breath. In the blood, they still propagate, and feed, and grow, consuming its oxygen, thus defeating its purification, and turning that stream of otherwise healthful and invigorating nutrition into a stream of effete and corrupt matter—a sewer rather than a river of life—or at best an impoverished and impure supply for the support of existence.

The same pestilential but invisible hosts of bacteria, mustered and bred in the close filthiness of Oriental cities, and jungles, swarm out as Asiatic cholera on the wings of the wind, sweeping the wide world with havoc. Settled on the tropical shores of the Eastern Atlantic, they lie in wait for their victims in the sluggish and terrible coast fever. On the western coast of the same ocean, perhaps from some cause connected with oceanic or atmospheric currents, they make devastating irruptions inland, as yellow fever, in every direction where the walls of their enclosure are low enough to be freely passed. These, let us remember, are all essentially the same organic poison that is engendered wherever life and death are plying their perpetual game; and this, like Cleopatra's "worm, will do its kind" in the veins of man, wherever obstructions, natural or artificial, temporary or permanent, interfere with its prompt diffusion in the vastness of the general atmosphere. Our "house of life" stands generously open, for every "inmate bad" to come and go through the absorbent, unquestioned, except in the stomach, where the tangible poisons have to go by the act of swallowing and where they are often challenged and ejected. It seems at first thought very strange that we are not so well protected by natural instinct or sensibility from the subtle poisons of the atmosphere as from those that can affect us only by the voluntary act of swallowing. The obvious explanation, however, of this apparent neglect is that Nature protects us in general from gaseous poisons by her own system of ventilation; and if, when we devise houses, necessarily excluding that system, we fail to devise also a sufficient substitute for it, the consequences of such negligence are as fairly due as when we swallow tangible poison.

I have hitherto referred only to the dispersion of poisonous exhalations, as if the best and most necessary thing the atmosphere can do for us were to dilute the dose to a comparatively harmless potency. But this is now known to be not the true remedial process with respect to the zymotic germs. The most wonderful achievement of recent investigation reveals a philosophy of both bane and antidote that astonishes us with its simplicity as much as with its efficiency. At the moment when humanity stands aghast at the announcement that germs are not destroyed by disinfectants, comes the counter discovery that they are rendered harmless by oxygen. It seems that it makes no difference, really, of what sort or from what source are the bacteria that we take into the blood. The only material difference to us depends on the sort of atmosphere in which their hourly generations are bred. For example, the bacteria developed in confined air, from a simple infusion of hay, are found by experiment to be as capable of generating that most terrible of blood poisoners, the malignant pustule, as are the bacteria taken from the pustule itself.

On the other hand, the bacteria from the malignant pustule itself, after propagating for a few hours in pure and free air, become a perfectly harmless race, and are actually injected into the blood with impunity. The explanation of the strange discovery is this—note its extreme simplicity—bacteria bred in copious oxygen perish for want of it as soon as they enter the blood vessels; whereas those inured to an unventilated atmosphere for a few generations, which means only a few hours, are prepared to thrive and propagate infinitely within our veins; and that is the whole mystery of blood poisoning and zymotic diseases. Taken in connection with the narcotic or nerve-poisoning power of carbonic acid (to which all the classes of diseases resulting from colds are due), we have also in this simple but grand discovery the whole mystery of the question with which we set out—why free air is health, and why sickness is a purely domestic product. The restitution of natural health to mankind demands only, but demands absolutely, the constant diffusion in copious and continuous floods of atmospheric oxygen, of the nerve-poisoning carbonic acid of combustion (organic and inorganic), and of the blood-poisoning bacteria of organic decomposition.

We find, then, as a matter both of experience and of philosophy, that life or death, in the main and in the long run, turns on the single pivot of atmospheric movement or obstruction. The resistance of mere rising ground or dense vegetation to a free movement of the air from low-lying levels performs an obstructive office similar to that of the walls and roofs of houses, and with like effect. The invariable condition of unhealthy seasons and days is a state of rarefaction and stagnation of the atmosphere, when the poison-freighted vapor cannot be lifted and dispersed, and every one complains of the sultry, close, "muggy" (meaning murky) feeling of the air. Few reflect, when fretted by the boisterous winds of March, upon the vital office they perform in dispersing and sanitating the bacteria-laden exhalations let loose by the first warmth from the soaked soil and the macerated deposits of the former year.

The passing air, then, that we breathe so lightly, is on other business, and carries a load we little think of, and that is not to be trifled with. This grand carrier of nature, on business of life or death, must not be detained, must not be hindered! or they who interfere with the business by restraining walls and roofs will take the consequences. It is a good deal like stopping a bullet, except as to consciousness and suddenness of effect.

That men live at all in their obstructed and therefore poison-loaded atmosphere, is a proof of the wonderful efficiency of the protective economy of Nature within us; so wonderful, indeed, that few can believe the fact of living to be consistent with the real existence of such a deadly environment as science pretends to reveal. It is a common impression, therefore, that actual results fail to justify the alarm sounded by sanitarians. Hence the necessity for calling attention at the outset to an ample and manifest equivalent for the deadly dose of confined exhalations taken daily by all civilized men. We perceive that that dose is not lost, like the Humboldt River, in a "sink," but reappears, like the wide-sown grass, in a perennial and universal crop of diseases, almost numberless and ever increasing in number, peculiar to house-dwellers. The trail of these plagues stops nowhere else; it leads straight to the imprisoned atmosphere in our artificial inclosures, and there it ends. That marvelous protective economy of Nature within us, to which we have referred, is no perpetual guaranty against the consequences of our negligence; it is only a limited reprieve, to afford space for repentance; and unless we hasten to improve the day of grace, the suspended sentence comes down, upon us at last with force the more accumulated by delay.

Now, therefore, the grand problem of sanitary science (almost untouched, almost unrecognized) proves to be no other and no less than this:

What can be done to remedy the obstructive nature of an inclosure, so that its gaseous contents shall move off, and be replaced by pure air, as freely, as rapidly, and as incessantly, as in the open atmosphere?

It happens to be the most necessary preliminary in approaching this problem, to show how not to do it, for that, respectfully be it spoken, is what we have hitherto practiced, as results abundantly prove. Fallacies, both vulgar and scientific, obstruct our way. A fundamental fallacy respects the very nature of the work, which is supposed to be to get in fresh air. In point of fact, this care is both unnecessary and comparatively useless. Take care of the bad air, and the fresh air will take care of itself. Only make room for it, and you cannot keep it out. On the other hand, unless you first make room for it, you cannot keep it in; pump it in and blow it in as you may, you only blow it through, as the Jordan flows comparatively uncontaminated through the Dead Sea. This is a law of fluids that must be kept in view. The pure air is quite as ready to get out as to get in; while the air loaded with poisonous vapors is as sluggish as a gorged serpent, and will not budge but on compulsion. Such compulsion the grand system of wind suction, actuated by the sun, supplies on the scale of the universe; and this we must imitate and adapt for our more limited purposes.

It would seem as if we need not pause to notice so shallow though common a notion as that which usually comes in right here, namely, that confined air will move off somehow of itself, if you give it liberty; being supposed to be much like a cat in a bag, wanting only a hole to make its escape. Air is ponderable matter—as much so as lead—and equally requires force of some kind to set it or keep it in motion. But applied philosophy itself relies on a fallacious, or, at best, inadequate source of motive power for ventilation. It gravely prescribes ventilating flues and even holes, and promises us that the warmed air within the house will rise through these flues and holes, carrying its impurities away with it, from the pressure of the cooler and denser air without. But we very well know that the best of flues and chimneys will draw only by favor of lively fires or clear weather. They fail us utterly when most needed, in warm and murky weather, when the barometer is low, and the thin atmosphere drops, down its damp and dirty contents, burying us to the chimney tops in a pestilent congregation of vapors.

Nevertheless, so far as I can discover, these holes and flues, at best a little fire at the bottom of the latter, are the sole and all-sufficient expedients of science and architecture for ventilation to this day, in spite of their total failure in experience. I can find nothing in standard treatises or examples from philosophers or architects, beyond a theoretical calculation on so much expansion of air from so many units of heat, and hence so much ascensional force inferred in the ventilating flue—a result which never comes to pass, yet none the less continues to be cheerfully relied on. Unfortunately for the facts, they contradict the philosophy, and are only to be ignored with silent contempt. A French Academician's report on the ventilation of a large public building, lately reprinted by the Smithsonian Institution, states with absolute assurance and exactness the cubic feet of air changed per minute, with the precise volume and velocity of its ascension, by burning a peck of coal at the bottom of the trunk flue. No mention is made of the anemometer or any other gauge of the result asserted, and we are left to the suspicion that it is merely a matter of theoretical inference, as usual; for every one who has had any acquaintance with practical tests in these matters knows that no such movement of air ever takes place under such conditions, unless by exceptional favor of the weather.

I have seen a tall steam boiler chimney induce through a four inch pipe a suction strong enough to exhaust the air from a large room as fast as perfect ventilation would require. But this, it is well known, requires four hundred or five hundred degrees of heat in the chimney. I never saw an ordinary domestic fire of coals produce any noticeable ventilating suction, without the use of a blower, urging the combustion to fury, and I presume nobody else ever did.

But, while nobody ever saw an active suction of air produced by the mere heat of a still or unexcited fire—unless the quantity of heat were on a very large scale—everybody has seen a roaring current sucked through the narrowed throat of a chimney or a stove by a blazing handful of shavings, paper, or straw. It is very remarkable, when you come to think of it, that the burning of an insignificant piece of paper, with less heat in it, perhaps, than a pea of anthracite, will cause a rush of air that a bushel of anthracite cannot in the least degree imitate. It is not only a curious but a most important fact. In short, it is the cardinal fact on which ventilation practically turns. But what is the nature of it? There are three factors in the phenomenon. In the first place, the mechanical peculiarity of flame, or gas in the moment of combustion, as compared with a gas like air merely heated, is an almost explosive velocity of ascent. The physical peculiarity from which this results is the intensity of its heat—commonly stated at 2,000 degrees, as to our common illuminating gas—acting instantaneously throughout its mass, just as in gunpowder. The gas goes up the flue in its own flash, like the ignited charge in the barrel of a gun: the burning coals can only send, and by a leisurely messenger, namely, the moderately heated gases, and contiguous air, that rise only by the gravitation or pressure of the surrounding atmosphere.

And yet it is not the small flame itself that roars in the chimney but the rush of air induced by it. The semi-explosion of flame is but for an instant, though constantly renewed, and its explosive impulse cannot carry its light products of combustion very far through stationary and resistant air. It is the induction of air carried with it by such semi-explosive impulse (under proper mechanical conditions) that is strange to our observation and understanding, and is the second factor in the phenomenon we are accounting for and preparing to utilize.

The process, as it actually is, may be clearly exhibited by a very simple means. Let anyone take a tube, say an inch in diameter—a roll of paper will do as well as anything—and, applying it closely to his mouth, try the whole force of his lungs through it upon any light object. The amount of effect will be found surprisingly small; and unless the tube is a short one, it will be so far absorbed by friction and atmospheric resistance as to be almost imperceptible. Then let him hold the same tube near to the mouth, but not in contact, and repeat the experiment. With the best adjustment, the effect may be described as tenfold or fifty-fold, or almost any fold—the effect of the simple blowing being merely nominal as compared with the induced current added by blowing into the tube instead of in it. The blast enters the free and open orifice with all the contiguous air which its surface friction and the vacuum of its movement can involve in its rolling vortex. While the entrance is thus crowded with pressure, the exit is free; and the result at the exit is a blast of well sustained velocity and magnified volume; ready itself to repeat the miracle on a still larger scale if provided with the apparatus for doing so. To test this, now place a second and larger tube in such position as to prolong the first in a straight line, but with a slight interval between the meeting ends; so that the blast, as magnified in volume in entering the first tube, may enter in like manner the second tube and be magnified again. With correct adjustments this experiment will prove more surprising than the first. Put on a third and still larger tube in the same way, and still larger surprise will meet a still larger volume and force of blast, like a stiff breeze set in motion by the puny effort of a single expiration. Of course, the prime impulse must bear a certain proportion to the result; and the inductive or tractional friction of the initial blast, of flame or breath, will be used up at length unless re-enforced. In ventilating practice, there is such re-enforcement, from an excess of gravity in the cooler atmosphere outside the flue in which the flame is operating with its heat as well as its ascensional traction; so that there has been found no limit to the extensions and fresh inductions that may be added to the first or trunk flue, with increase rather than diminution of power at every point. But the terms on which such extensions must be made have been referred to in our illustration, and must be accurately ascertained and observed. They constitute what is, in effect, the third factor in the phenomenon of a roaring draught, and also, therefore, ineffective ventilation. That is, the entering or induced current of air must always find its channel of progress and exit certain correct degrees larger than the opening by which it entered. Every one knows that a stove or chimney wide open admits of but little suction in connection with even the blaze of paper or shavings.

The mobility of air seems almost preternatural, when the proper conditions for setting a current in motion are supplied. But without a current established, it is surprising in turn to find how obstinately and elusively immovable it can be. It is like tossing a feather; or trying to drive a swarm of flies; dodging and evading every impulse applied. But, given a flue, to define and conduct a stream; an upright flue, to take advantage of the slighter gravity of the warmed air within it; and a flue contracted at the inlet and expanded as it rises, so as to free, diffuse, and lighten the column of air, toward the exit; then, initiate an induced current of air at the inlet, by the injection of a jet of gas in the state of semi-explosive action called flame; the pressure pushing upward from the crowded entrance finds easier way and less resistance the farther it goes in the expanding flue; the warmth and reduced gravity of the stream comes in as an auxiliary in overcoming friction and any exceptional obstruction in the state of the atmosphere; and now, as the ball is once set rolling, with a little aid instead of resistance from gravitation, its initial impulse all the while sustained by the gas jet, and friction reduced to a very small incident—there is nothing to prevent the current rolling on with accelerated velocity (within the limitations imposed by increasing friction) and rolling on forever. I might, if I had time, add a curious consideration of the law of vortex motion in elastic fluids, demonstrated by Helmholtz, which relieves the motion of such fluids from friction, as wheels facilitate the movement of a solid; and which also sucks into the rolling vortex the contiguous air, thus entraining it, as we have seen, so much more effectively than could be done by a direct and rigid current, like a jet of water, for instance. A wheel set in motion on an almost frictionless bearing of metalline, runs without perceptible abatement of velocity, until one begins to involuntarily question whether it will ever stop. In the all but free winds that roll with minimized friction in the higher atmosphere, there seems to be a self-moving force; so persistent is simple momentum in a mass so infinitesimally obstructed and so infinitely wheeled. An active current of air in a ventilating flue is only less perfect in the same conditions; and so it is quite conceivable, and not incredible, that such a current may be gradually established and thenceforward permanently maintained by a small motor flame barely more than enough to overbalance the minimized friction. This is not a supposed or theoretically inferred fact, like the facts of ventilation sometimes alleged by theorists. On the contrary, the theory I have offered is merely an attempt to explain facts that I have witnessed and that anyone can verify with the anemometer. But the theory by no means covers the art and mystery of ventilation; for ventilation is truly an art as well as a mystery. The art lies in a consummate experience of the sizes, proportions, and forms of flues, their inlets, expansions, and exits, with many other incidental adaptations necessary, in order to insure under all circumstances the regular exhaustion of any specific volume of air required, per minute. And this art has by one man been achieved. It would be a double injustice if I should neglect from any motive to inform my audience to whom I am indebted for what I know about ventilation practically, and even for the knowledge that there is any such fact as a practicable ventilation of houses; one who is no theorist, but who has felt his way experimentally with his own hands, for a lifetime, to a practical mastery of the art to which I have attempted to fit a theory; every one present who is well informed on this subject must have anticipated already in mind the name of Henry A. Gouge.