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Faraday's great discovery was, in fact, that when the pole of a magnet is moved into, or moved out of, a coil of wire, the motion produces, while it lasts, currents of electricity in the coil. Such currents are known as "induced currents;" and the action is called magneto-electric "induction." The momentary current produced by plunging the magnet pole into the wire coil or circuit is found to be in the opposite direction to that in which a current must be sent if it were desired to attract the magnet pole into the coil. If the reader will look back to Fig. 10 he will see that a north magnet pole is being attracted in from behind into a circuit round which, as he views it, the current flows in an opposite sense to that in which the hands of a clock move round. Now, compare this figure with Fig. 12, which represents the generation of a momentary induced current by the act of moving the north pole, N, toward a wire ring, which is in this case connected with a little detecter galvanometer, G. The momentary current flows round the circuit (as seen by the spectator from the front) in the same sense as the movement of the hands of a clock. The induced current which results from the motion is found, then, to be in a direction exactly opposed to that of the current that would itself produce the same movement of the magnet pole. If the north pole, instead of being moved toward or into the circuit, were moved away from the circuit, this motion will also induce a transient current to flow round the wire, but this time the current will be in the same sense as that in Fig. 10, in the opposite sense to that in Fig. 12. Pulling the magnet pole away sets up a current in the reverse direction to that set up by pushing the pole nearer. In both cases the currents only last while the motion lasts.
Now in the first article it was pointed out that the lines of force of the magnet indicate not only the direction, but the strength of the magnetic forces. The stronger the pole of the magnet is, the greater will be the number of lines of force that radiate from its poles. The strength of the current that flows round a circuit is also proportional to the number of lines of force which are thereby caused to pass (as in Fig. 9) through the circuit. The stronger the current, the more numerous the lines of force that thread themselves through the circuit. When a magnet is moved near a circuit near it, it is found that any alteration in the number of lines of force that cross the circuit is accompanied by the production of a current. Referring once more to Fig. 10, we will call the direction of the current round the circuit in that figure the positive direction; and to define this direction we may remark that if we were to view the circuit from such a point as to look along the lines of force in their own direction, the direction of the current round the circuit will appear to be the same as that of the hands of a clock moving round a dial. If the magnet, N S, be now drawn away from the circuit so that fewer of its lines of force passed through the circuit, experiment shows the result that the current flowing in circuit will be for the moment increased in strength, the increase in strength being proportional to the rate of decrease in the number of lines of force. So, on the other hand, if the magnet were pushed up toward the circuit, the current in the circuit would be momentarily reduced in strength, the decrease in strength in the current being proportional to the rate of increase in the number of lines of force.
Similar considerations apply to the case of the simple circuit and the magnet shown in Fig. 12. In this circuit there is no current flowing so long as the magnet is at rest; but if the magnet be moved up toward the circuit so as to increase the number of lines of force that pass through the circuit, there will be a momentary "inverse" current induced in the circuit and it will flow in the negative direction. While if the magnet were moved away the decrease in the number of lines of force would result in a transient "direct" current, or one flowing in the positive direction.
It would be possible to deduce these results from an abstract consideration of the matter from the point of view of the principle of conservation of energy. But we prefer to reserve this point until a general notion of the action of dynamo-electric machines has been given.
The following principles or generalized statements follow as a matter of the very simplest consequence from the foregoing considerations:
(a) To induce a current in a coil of wire by means of a magnet there must be relative motion between coil and magnet.
(b) Approach of a magnet to a coil or of a coil to a magnet induces currents in the opposite direction to that induced by recession.
(c) The stronger the magnet the stronger will be the induced currents in the coils.
(d) The more rapid the motion the stronger will be the momentary current induced in the coils (but the time it lasts will, of course, be shorter).
(e) The greater the number of turns in the coil the stronger will be the total current induced in it by the movement of the magnet.
These points are of vital importance in the action of dynamo electric generators. It remains, however, yet to be shown how these transient and momentary induction currents can be so directed and manipulated as to be made to combine into a steady and continuous supply. To bring a magnet pole up toward a coil of wire is a process which can only last a very limited time; and its recession from the coil also cannot furnish a continuous current since it is a process of limited duration. In the earliest machines in which the principle of magneto-electric induction was applied, the currents produced were of this momentary kind, alternating in direction. Coils of wire fixed to a rotating axis were moved past the pole of a magnet. While the coil was approaching the lines of force were increasing, and a momentary inverse current was set up, which was immediately succeeded by a momentary direct current as the coil receded from the pole. Such machines on a small scale are still to be found in opticians' shops for the purpose of giving people shocks. On a large scale alternate current machines are still employed for certain purposes in electric lighting, as, for example, for use with the Jablochkoff candle. Large alternate-current machines have been devised by Wilde, Gramme, Siemens, De Meritens, and others.—Engineering.
* * * * *
ON THE UNIT WEIGHT AND MODE OF CONSTITUTION OF COMPOUNDS.
Dr. Odling delivered a lecture on the above before the Chemical Society, London, February 2, 1882.
The lecturer said that it had been found useful to occasionally bring forward various points of chemical doctrine, on which there were differences of opinion, to be discussed by the society. On this occasion he wished not so much to demonstrate certain conclusions, or to make a declaration of his opinions, as to invite discussion and a thoughtful consideration of questions of importance to chemists. Originally three questions were proposed: First, Is there any satisfactory evidence deducible of the existence of two distinct forms of chemical combination (atomic and molecular)? Second, Is the determination of the vapor density of a body alone sufficient to determine the weight of the chemical molecule? Third, In the case of an element forming two or more distinct series of compounds, e.g., ferrous and ferric salts, is the transition from one series to another necessarily connected with the addition or subtraction of an even number of hydrogenoid atoms? He would, however, limit himself to the first of these questions; at the same time the three questions were so closely associated with one another that in discussing the first it was difficult to know where to begin. The answer to this question (Is there any satisfactory evidence deducible of the existence of two distinct forms of chemical combination?) depends materially on the view we take of the property called in text-books valency or atomicity; and before discussing the question it is important to have a clear idea of what these words valency and atomicity really mean. It is necessary, too, to start with some propositions which must be taken for granted. These propositions are: First, that in all chemical changes, those kinds of matter which we commonly call elementary, do not suffer decomposition. Second, That the atomic weights of the elements as received are correct, i.e., that they do really express with great exactitude the relative weights of the atoms of the individual elements. If we accept these two propositions, it follows that hydrogen can be replaced atom for atom by other elements not only by the hydrogens but by alkali metals, etc. Hydrogen is, it may here be remarked, an element of unique character; not only can it be replaced by the elements of the widely different classes represented by chlorine and sodium, but it is the terminal of the series of paraffins, C{n}H{2n}; C{3}H{6}, C{2}H{4}, H{2}. The third proposition which must be taken for granted is, that the groups of elements, C{2}H{5}, CH{3}, behave as elements, and that these radicals, ethyl, methyl, etc., do not suffer decomposition in many chemical reactions.
Now as to valency or atomicity, accepting the received atomic weights of the elements, it is certain that there are at least four distinct types of hydrogen compounds represented by ClH, OH_{2}, NH_{3}, CH_{4}. The recognition of these types, and their relations to each other as types, was one of the most important and best assured advances made in theoretical chemistry. When we compare the formula of water with that of hydrochloric acid, we find that there is twice as much hydrogen combined with one atom of oxygen as there is combined with one atom of chlorine; and in a great many other instances, we find that we can replace two atoms of chlorine by one atom of oxygen, so that we get an idea of the exchangeable value of these elements, and we say that one atom of oxygen is worth two of chlorine, or is bivalent; similarly, nitrogen is said to be trivalent. The meaning attached to the word "valency," is simply one of interchangeability, just as we say a penny is worth two halfpennies or four farthings. The question next arises, is the valency of an element fixed or variable? If the word be defined as above, it is absolutely certain that the valency varies. Thus, tin may be trivalent, SnCl_{2}, or tetravalent, SnCl_{4}. Accordingly elements have been classed as monads, dyads, triads, etc. The lecturer objected most strongly to the word "atomicity;" he could not conceive of one atom being more atomic than another; he could understand the atomicity of a molecule or the equivalency of an atom, but not the atomicity of an atom; the expression seemed to him complete nonsense. He next considered the possibility of assigning a fixed limit to this valency or adicity of an atom, and concluded that the adicity was not absolutely fixed, but was fixed in relation to certain elements, e.g., C never combines with more than four atoms of H; O never more than two atoms of H, etc. The adicity of an element when combined with two or more elements is usually higher than when combined with only one, e.g., NH_{3}, NH_{4}Cl. The term "capacity of saturation," may be used as a synonym for adicity, if care be taken to distinguish it from other kinds of saturation, such as an acid with an alkali, etc. Adicity is, however, quite distinct from combining force; the latter is indicated by the amount of heat evolved in the combination.
The lecturer then proceeded to criticise a statement commonly found in text books, that chemical combination suppresses altogether the properties of the combining bodies. The reverse of this statement is probably true. To take the case commonly given of the combination of copper and sulphur when heated; this is good as far as it goes, but there are numerous instances, as ClI, SSe, etc., where the original properties and characters of the combining elements do not completely disappear. The real statement is that the original properties of the elements disappear more or less, and least when the combination is weak and attended with the evolution of a slight amount of heat, and in every case some properties are left which can be recognized. So with reference to the question of atomic and molecular combination, as atomic combination does not necessarily produce change, it does not differ in this respect from what is usually called molecular combination.
The lecturer then referred to an important difference in the adicity of chlorine and oxygen. Chlorine can combine with methyl or ethyl singly. Oxygen can combine with both and hold them together in one molecule. The recognition of this fundamental difference between chlorine and oxygen, this formation of double oxides as opposed to single chlorides, marks an epoch in scientific chemistry.
The lecturer then considered the subject of chemical formulae; it is the bounden duty of every formula to express clearly the number of atoms of each kind of elementary matter which enters into the constitution of the molecule of the substance. A formula may do much more than this. If we attempt to express too much by a complex formula we may veil the number of atoms contained in it. This difficulty may be avoided by using two formulae, a synoptic formula giving the number of atoms present, and a complex formula perhaps covering half a page, giving the constitution of the molecule. But between the purely synoptic formula and the very elaborate formula there are others—contracted formulae—which labor under the disadvantage, as a rule, of being one-sided, and so create a false impression as to the nature of the substance. Thus, for instance, to take the formula of sulphuric acid, H_{2}SO_{4}. This suggests that all the oxygen is united to the S; (HO)_{2}SO_{2} suggests that two atoms of hydroxyl exist in the molecule; then, again, we might write the formula HSO_{2}OH, or H_{2}OSO_{3}. All of these are justifiable, and each might be useful to explain certain reactions of sulphuric acid, but to use one only creates a false impression. The only plan is to use them variously and capriciously, according to the reaction to be explained. Again, ethyl acetate may be written—
H_{3}C H_{2}C/ O / OC H_{3}C/
Or condensed—
H{5}C{2} }O H{3}C{2}O/
Or H_{5}C_{2}O.C_{2}H_{3}O, or H_{5}C_{2}.C_{2}H_{3}O_{2}. Now each of these two latter formulae is a partial formula, each represents a one-sided view; it is justifiable if you use both, but unfair if you use only one.
We now come to the question as to the existence or non-existence of two distinct classes of compounds, one in which the atoms are combined directly or indirectly with each other, and the other in which a group of atoms is combined as an integer with some other group of atoms, without any atomic connection by so-called molecular combination. These two modes of combination are essentially distinct. The question is not one of degree. Are there any facts to support this theory that one set of compounds is formed in one way, another in a different way? Take the case of the sulphates: Starting with SO{3}, we can replace one atom of O by HO{2}, and obtain SO{2}(HO){2} or H{2}SO{4}; replacing a second atom, we get SO(HO){4} or H{4}SO{5}, glacial sulphuric acid, a perfectly definite body corresponding to a definite class of sulphates, e.g., H{2}MgSO{5}, Zn{2}SO{5}, etc. By replacing the third atom of O we get S(HO){6} or H{6}SOH{6}; this corresponds to a class of salts, gypsum, H{4}CaSO{6}, etc. These are admitted without dispute to be atomic compounds. Are we to stop here? We may write the above compounds thus: H{2}SO{4}, H{2}SO{4}H{2}O, H{2}SO{4}2H{2}O. If we measure the heat evolved in the formation of the two latter compounds, it is, for H{2}SO{4}+H{2}O, 6.272; H{2}SO{4}+2H{2}O, 3.092. But if we now take the compound H{2}SO{4}+3H{2}O we have heat evolved 1.744; so we can have H{2}SO{4}4H{2}O, etc. Where are we to draw the line between atomic and molecular combination, and why? It comes to this: All compounds which you can explain on your views of atomicity are atomic, and all that you cannot thus explain are molecular. Similarly with phosphates, arsenates, etc. In all these compounds it is impossible to lay one's finger on any distinction as regards chemical behavior between the compounds called atomic and those usually called molecular.
Two points remain to be mentioned: The first is the relationship between alteration of adicity and two series (ous and ic) of compounds. Tin is usually said to be dyad in stannous compounds and a tetrad in stannic compounds, but in a compound like SnCl_{2}AmCl, is not tin really a tetrad?
{Cl {Cl Sn {Cl {NH_{4}
and yet it is a stannous compound, and gives a black precipitate with H_{2}S; so that valency does not necessarily go with the series. The second point is that an objection may be urged, as, for example, in ammonium chloride (the lecturer stated above that here N was a pentad, the addition of the chlorine having caused the N to assume the pentadic character), it may be said, why should you not suppose that it is the chlorine "which has altered its valency, and that the compound should be written:
{H {H N { {H—Cl {H/
There is something to be said for this view, but on the whole the balance of the evidence is in favor of nitrogen being a pentad.
In conclusion the lecturer stated that his principal object was to direct the attention of chemists, and especially of young chemists, to the question: Is there or is there not any evidence derived from the properties, the decompositions, or the relative stabilities of substances to warrant us in believing that two classes of compounds exist: one class in which there is interatomic connection alone, and another in which the connection is molecular?
* * * * *
FRENCH TOILET ARTICLES.
Mr. Martenson, of St. Petersburg, who, it will be remembered, was one of the Russian delegates to the International Pharmaceutical Congress, has been analyzing a number of French preparations for the toilet, most of which are familiar to our readers, at any rate by name and repute.
1. Eau de Fleurs de Lys—(Planchon and Riet, Paris.)—An infallible banisher of freckles, etc., etc. The bottle contains 100 grammes of a milky fluid, made up of 97 per cent. of water, 2.5 per cent. of precipitated calomel, and a small quantity of common salt and corrosive sublimate, and scented with orange flower water.
2. Eau de Blanc de Perles.—The bottle contains 120 grammes of a weak alkaline solution, with a thick deposit of 15 per cent. of carbonate of lead, and scented with otto of roses and geranium.
3. Nouveau Blanc de Perle, Extra Fin.—(Lubin, Paris.)—The bottles contains 35 grammes of a liquid consisting of water, holding in suspension about equal parts of zinc oxide, magnesic carbonate, and powdered talc, perfumed with otto of roses.
4. Lait de Perles.—A close imitation of No. 3, the bottle holding nearly three times the quantity for the same price. The amount of the precipitate in this case is 20 per cent.
5. Lait de Perles.—(Legrand, Paris).—The bottles contain 65 grammes of a thick white fluid, the precipitate from which consists of zinc oxide and bismuth oxychloride, and is scented with rose water.
6. Lait Antiphelique.—(Candes and Co., Paris.)—Each bottle contains 140 grammes of a milky fluid, smelling strongly of camphor, and having an acid reaction. It contains alcohol, camphor, ammonic chloride, half per cent. of corrosive sublimate, albumen, and a little free hydrochloric acid.
7. Lait de Concombres.—The bottle contains 160 grammes of a very inelegantly made emulsion, smelling of very common rose-water, with an unpleasant twang about it, and giving a strongly alkaline reaction. It consists of soap, glycerin, and cotton seed oil, made into a semi-emulsion.
8. Creme de Fleurs des Lys; Blanc de Ville Onctueux.—About 30 grammes of a kind of weak ointment contained in a small pomatum pot prettily ornamented. It is simply a salve made of wax oil, and possibly lard, mixed with a large proportion of zinc oxide, and smelling of inferior otto of roses.
9. Pate de Velonas.-This paste consists of almond, and possibly other meal mixed with soap powder, and has a strong alkaline reaction. It is scented with orris-root.
10. Rouge Vegetal.—The box contains 81/2 grammes of raspberry colored powder, consisting chiefly of China clay and talc, tinted to the proper depth with extract of cochineal.
11. Rouge Extra Fin Fonce.—A small square bottle containing 11 grammes of a deep red solution, smelling of otto of roses and ammonia. It consists of a solution of carmine in ammonia, with an addition of a certain amount of alcohol.
12. Rouge de Dorin.—Extract des Fleurs des Indes.—A round pot containing a porcelain disk, covered with about 6 grammes of a bright red paste, which is a mixture of carthamin or safflower with talc. This rouge, which differs from all the others, is harmless and effectual, but must bear a high profit seeing that the ingredients cost only a few half-pence, while it sells in St. Petersburg at about 4s. 9d. a pot.
13. Etui Mysterieux ou Boite de Maintenon.—A prettily got-up box containing red and white paint, and two sticks of black and blue cosmetic for the eyebrows and veins, with camel's hair pencils for applying the latter. Sells in St. Petersburg at 6s. 4d.
14. Philidore.—Remede Specifique pour oter les Pellicules de la tete, etc.—The bottle contains 100 grammes of a strong alkaline solution smelling strongly of ammonia, and containing potash, ammonia, alcohol, glycerin, and eau de cologne.
15. Colorigene Rigaud.—A blue bottle containing 160 grammes of a clear fluid with a slight black deposit, consisting of a mixture of equal parts of a 14 per cent. solution of sodic hyposulphate, and a 4 per cent. solution of lead acetate. Of course the longer this solution is kept the more lead sulphate it deposits. It sells in St. Petersburg at 8s. per bottle. It is also stated to be much more powerful if used in conjunction with the Pommade Miranda Rigaud. This beats Mrs. Allen completely out of the field.—Pharmaceutische Zeitschrift fuer Russland.
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ON THE MYDRIATIC ALKALOIDS.
By ALBERT LADENBURG.
We translate the following important article, says the Chemists' Journal, from the Moniteur Scientifique of last month. It may be explained for the sake of our student readers that the word mydriatic is derived from the Greek mudriasis, which means paralysis of the pupil.
The synthetical researches which I have undertaken with a view to explain the constitution of atropine have shown me the necessity of studying the connection of atropine with the other alkaloids, which have an analogous physiological action. According to the early researches we could not discover any of these relationships which only become evident when we come to study the new discoveries which have been made in connection with the tropines, to which class belong both duboisine and hyoscyamine, which, although differing from atropine, are equally mydriatic in their action.
I.—ATROPINE.
Discovered by Mein in 1831 in the roots of belladonna. More thoroughly studied some time after by Geiger and Hesse, who confirmed Mein's results. Liebig next published an analysis of the alkaloid, which was afterward shown to be incorrect. He consequently modified his formula, and gave the following as the composition of atropine; C_{17}H_{23}NO_{3}. Liebig's amended analysis was afterward confirmed by Planta, who further showed that the alkaloid itself melted at 194 deg. F., and its double gold salt at 275 deg. F. It is worthy of remark that the first figure was considered correct until my researches proved the contrary. The physiological action of atropine, especially in relation to the eye, has been most carefully studied by several celebrated ophthalmologists, such as Graef, Donders, Bezold, and Bloebaum. Its chemical properties have also been the object of very extensive researches by Pfeiffer, Kraut, and Lassen. Pfeiffer first discovered that benzoic acid was one of the products of decomposition of atropine, and Kraut split atropine by means of baryta water into atropic acid, C_{9}H_{6}O_{2}, and tropine, C_{8}O_{15}NO. Lassen, who used hydrochloric acid, discovered the true products of the splitting up of atropine, viz., tropic acid, C_{9}H_{8}O_{3}, and tropine, C_{8}H_{15}N, and proved at the same time that atropic acid is easily formed by the action of boiling baryta water on tropic acid, while hydrochloric acid at all temperatures forms isatropic acid, an isomer of atropic acid. Kraut confirmed these results, and showed that atropic acid as well as cinnamic acid gives benzoic acid by oxidation, and hydratropic acid (the isomer of phenylpropionic acid) by reduction with sodium amalgam. These results are sufficient to show that tropic acid may have one of the following two formulae.
I II
CH{2}OH CH{3} / / C{4}H{5}CH or C{8}H{5}—C—OH OOHO COOH
Fittig and Wurster, who discovered atrolactic acid, C_{2}H_{10}O_{3}, an isomer of tropic acid, gives tropic acid the second formula, while Burgheimar and myself have shown that it is the true formula of atrolactic acid. Lately we have succeeded in performing the complete synthesis of atropic acid, and the artificial preparation of atropine has been greatly facilitated since I have shown that we can easily reconstruct atropine by starting from its products of decomposition, tropic acid, and tropine.
Before my researches nothing was known of the constitution of tropine. New unpublished researches into this problem have shown that it closely resembles neurine,[1] a body which I hope will speedily lead us to the complete synthesis of atropine.
[Footnote 1: As we shall probably hear a great deal about this alkaloid, it may be as well to state that, although found in the brain and liver, it may be prepared synthetically by the action of ethylene oxide, (CH_{2})_{2}O, water, H_{2}O, and trimethyiamine, N(CH_{3})_{3}. Its constitution is that of trimethyl-ethylene-hydrate-ammonic-hydrate, and has the following constitutional formula:
{ (CH_{2})_{2}OH { CH_{3} N { CH_{3} { CH_{3} { OH
or in other words, it is the hydrate of trimethyl-hydrethylene-ammonium.]
The fusing point of atropine is not 194 deg. F., as stated by Planta, but 237 deg. F. Crystallized from not too dilute alcohol it forms crystals which are aggregations of prisms. Toluene, alcohol, and chloroform all dissolve atropine readily. Its double gold salt is very characteristic. It is generally precipitated in the form of an oil which solidifies rapidly and may be crystallized from hot water after the addition of a little hydrochloric acid. This clouds in cooling, and after a certain time it separates in small crystals of indeterminate form which unite in warty concretions. After drying the salt forms a dull powder, melting between 275 deg. F. and 280 deg. F. It also melts in boiling water, and its aqueous solution exposed to the light is partially reduced, 100 grammes of water acidulated with 10 cubic centimeters of 1.190 deg. solution of hydrochloric acid dissolves 0.137 gramme of the gold salt at 136 deg. F. to 140 deg. F.
I should fancy that the above particulars are sufficent to completely differentiate atropine from all the other mydriatic alkaloids.
II.—THE ATROPINE OF DATURA STRAMONIUM.
Planta has already tried to show that atropine is identical with the daturine obtained by Geiger and Hesse, founding his opinion on facts which we nowadays look upon as doubtful. This identity was generally admitted by all chemists. The pharmacologists, headed by Soubeiran, Erhardt, Schroff, and Poehl, were much more reserved in their judgment. I thought it as well, therefore, to recommence the study of daturine, the more so as I had already determined the incorrectness of the long accepted point of fusion of atropine, and that my researches on hyoscyamine convinced me that this base is an isomer of atropine, although very analogous to it. I have also shown that Merck's daturine differs from atropine, and is merely pure hyoscyamine. A short time afterward there appeared a paper by Schmidt which again asserted the identity of daturine and atropine. I therefore requested Mr. Merck, of Darmstadt, to send me all the bases which he obtained from datura. This eminent manufacturer was good enough to comply with my request, and sent me two products, one of which was marked "light daturine," the other "heavy daturine," the separation of which was effected in the following manner: The solution of crude daturine in concentrated alcohol was mixed with a little hot water; this treatment caused the deposition of the "heavy daturine," while the "light daturine" remained in the mother liquor. The "heavy daturine," of which only a small quantity is obtainable, is far from being a body of definite composition, that is to say, it is a mixture of atropine and hyoscyamine. If we convert the base into a double gold salt we obtain by a single crystallization a dull looking salt, melting at from 275 deg. F. to 280 deg. F., the appearance of which is very different to that of atropine. I have succeeded in splitting up "heavy daturine" by two different methods. By recrystallizing the gold salt six times from boiling water, the salt of hyoscyamine, which melts at from 316 deg. F. to 323 deg. F., crystallizes our first, and by the successive evaporation of the mother liquor at last obtain the pure gold salt of atropine, which melts at 275 deg. F. to 280 deg. F. If we only want to isolate the atropine, it is better to crystallize the free base two or three times from alcohol at 50 per cent., always taking the earliest formed crystals.
These facts prove the presence of atropine in datura; but while Planta and Schmidt assert that only this alkaloid is found in the plant, I have proved that the proportion of atropine in it is but small, while its richness in hyoscyamine is great. I think, therefore, that both Planta and Schmidt must have worked with a mixture of atropine and hyoscyamine. It is true that Schmidt had received pure atropine under the name of daturine, for I have proved most conclusively that the so-called daturine supplied by Trommsdorff, of Erfurt, is pure atropine and nothing else. It has no action whatever on polarized light.
III.—HYOSCYAMINE FROM HYOSCYAMUS.
Discovered by Geiger and Hesse in 1833. It was first obtained in the form of needles, which were much more soluble than atropine. In the pure state it forms a viscous mass with a repulsive odor. These researches were repeated by Thibout, Kletinski, Ludwig, Lading, Bucheim, Wagymar, and Renard.
Hoehn and Reichardt have recently studied hyoscyamine in a very complete manner. They have obtained the body in the form of warty concretions as soft as wax, and melting at 194 deg. F., having a formula according to them of C_{15}H_{23}NO_{3}. They have also studied the splitting up of the alkaloid by means of baryta water, and have obtained an acid which they have named hyoscinic acid, and which melts at about 219 deg. F., and a basic body, hyoscine, C_{6}H_{13}N. They represent the reaction as follows:
C{15}H{23}NO{3} = C{9}H{10}O{3} + C{6}H{13}N.
According to this view hyoscyamine ought to be the hyoscinate of hyoscine, or at any rate an isomer of this body. It is to be remarked that they compare hyoscinic acid not with tropic acid, of which it possesses the composition, but with atropic acid, C_{9}H_{8}O_{2}. I have worked with the hyoscyamine of both Merck and Trommsdorff, as well as with a product which I obtained from hyoscyamus seeds myself. The best way of purifying the alkaloid is by recrystallizing its gold salt several times, so as to obtain it in brilliant yellow plates, melting at 320 deg. F. By passing a stream of hydrosulphuric acid gas through the liquor the gold is precipitated in the form of sulphide. The liquid is filtered and evaporated, precipitated by an excess of a strong solution of potassium carbonate, and the alkaloid extracted by chloroform. The solution is dried over carbonate of potassium, and part of the chloroform is distilled off. By leaving the solution to evaporate spontaneously the alkaloid is obtained in silky crystals. The crystals are then dissolved in alcohol, which, on being poured into water, parts with them in the same form.
Hyoscyamine crystallizes in the acicular form, with greater difficulty even than atropine, it also forms less compact crystals. Its fusing point is 149.6 deg. F. I have not yet succeeded in crystallizing any of its more simple salts. The double platinum salt melts at 392 deg. F., with decomposition. The double gold salt, which has been described above, does not melt in boiling water, and its aqueous solution is reduced neither by boiling nor by long exposure to light. By leaving the hot saturated solution to cool it does not cloud, but the double salt separates pretty rapidly in the form of plates.
One liter of water containing 10 cubic centimeters of hydrochloric acid at 1.19 deg. dissolves 65 centigrammes of the salt at 146 deg. F.
These characteristics allow us to differentiate atropine and hyoscyamine, the reactions of which are almost identical, as will be seen from the following table, which shows the action of weak solutions of the acids named on the hydrochlorates of the bases:
Reagents. Hyoscyamine. Atropine.
Picric acid. An oil solidifying Crystalline precipitate. immediately into tabular crystals.
Mercuropotassic White cheesy Same. iodide. precipitate.
Iodized potassic An immediate A brown oil crystallizing iodide. precipitate of after a time. periodate.
Mercuric chloride. Same as picric acid. Same.
Tannic acid. Slight cloud. Cloud hardly visible.
Platinum chloride. O. O.
(To be continued.)
* * * * *
DETECTION OF SMALL QUANTITIES OF MORPHIA.
By A. JORISSEN.
The solution of morphia, free from foreign bodies, is evaporated to dryness, and the residue is heated on the water bath with a few drops of sulphuric acid. A minute crystal of ferrous sulphate is then added, bruised with a glass rod, stirred up in the liquid, heated for a minute longer, and poured into a white porcelain capsule, containing 2 to 3 c.c. strong ammonia. The morphia solution sinks to the bottom, and where the liquids touch there is formed a red color, passing into violet at the margin, while the ammoniacal stratum takes a pure blue. The reaction is very distinct to 0.0006 grm. Codeine does not give this reaction. If sulphuric acid at 190 deg. to 200 deg. is allowed to act upon morphia, there is ultimately formed an opaque black green mass. If this is poured dropwise into much water, the mixture turns bluish, and if it is then shaken up with ether or chloroform, the form takes a purple and the latter a very permanent blue. Codeine gives the same reaction, but no other of the alkaloids. This reaction can be obtained very distinctly with 0.0004 grm. of morphia.
* * * * *
ON THE ESTIMATION OF MANGANESE BY TITRATION.
[Footnote: From Jernkontorets Annaler, vol. xxxvi.—Iron.]
By C. G. SARNSTROM.
If we dissolve black oxide of manganese, permanganate of potash, or any other compound of manganese of a higher degree of oxidation than the protoxide in hydrochloric acid, we obtain, as is well known, a dark colored solution of perchloride of manganese, which, when heated to boiling loses color pretty rapidly, chlorine being given off, until finally only protochloride remains. This decomposition also proceeds at the common temperature, though much more slowly, and we may therefore say that manganese when dissolved in hydrochloric acid always tends to descend to its lowest, and, considered as a base, strongest degree of oxidation, which is not raised to a higher degree even by chameleon solution. In slightly acid, neutral, or alkaline solutions on the other hand, protoxide of manganese absorbs oxygen with great avidity and forms with it different compounds, according to the means of oxidation employed. Thus, for example, manganese is slowly deposited from an ammoniacal solution, when it is permitted to take up oxygen from the air, as hydrated sesquioxide, and from neutral or alkaline solutions, as hydrated peroxide on the addition of chlorine, bromine, or chameleon solution. For if to an acid solution of protochloride of manganese we add a solution of bicarbonate of soda, as long as carbonic acid escapes or till the free acid is saturated and the protochloride of manganese converted into carbonate of protoxide of manganese, which forms with bicarbonate of soda a soluble double salt, resembling the carbonate of lime and magnesia, we obtain a solution which is, indeed, acid from free carbonic acid, but has a slight alkaline reaction with litmus paper, and with the greatest ease deprives chameleon solution of its color, the permanganic acid being reduced and the protoxide of manganese being oxidized to peroxide, which is precipitated as hydrate. This reaction proceeds according to the formula,
3MnCO{3} + 2KMnO{4} + H{2}O = 2KHCO{3} + 5MnO{2} + CO{2}
and it may be employed for estimating the content of manganese by titration. As follows from the formula two equivalents of permanganate of potash are required for the titration of three equivalents of protoxide of manganese, which has also been established by direct experiments, as well as that the escape of carbonic acid indicated by the formula actually takes place. The precipitate of manganese is dissolved either in water to which 0.5 per cent. of hydrochloric acid has been added, or in boiling nitric acid. When manganese occurs along with iron, which in general is the case, we must take care that the iron in the solution is in the state of peroxide, which is precipitated on the addition of the bicarbonate of soda, and is allowed to remain as a precipitate, because it does not affect the titration injuriously. The removal of this precipitate by filtering would be more loss than gain, partly because there would be a risk of losing manganese in this way, partly because the precipitate of manganese, which occurs immediately on the addition of the chameleon solution, proceeds both more rapidly and with greater completeness in the presence of the iron precipitate than otherwise. This appears to be caused by the iron precipitate as it were inclosing, and mechanically drawing down the light manganese precipitate, provided a weak chemical union between the two precipitates does not even take place, depending on the tendency of peroxide of manganese to behave toward bases, as, for instance, hydrate of lime as an acid. Hence it thus follows that it ought to be arranged that a sufficient quantity of iron[1] (at least the same quantity as of manganese) be present in the liquid at titration, also that time be given for the precipitate to fall, so that the color of the solution may be observed between every addition of chameleon solution.
[Footnote 1: For this in case of need a solution of perchloride of iron free of manganese may be employed.]
When the content of manganese is large, it is sometimes rather long before the solution is ready for titration. The reason of this appears to be that a part of the manganese is first precipitated as hydrated sesquioxide, which is afterward oxidized to hydrated peroxide, for the upper portion of the liquid may sometimes be colored by chameleon, while the lower portion, which is in closer contact with the precipitate, is less colored or absolutely colorless. From this we also see how advisable it is to stir the liquid frequently during titration. Toward the close of it, it is also advantageous, when the contents of manganese are large, to warm the solution to about 50 deg. C., because the removal of color is thereby hastened. When the fluid, which is well stirred after each addition of chameleon, has obtained from it a perceptible color, which does not disappear after several stirrings, the whole of the manganese is precipitated and the color of the solution remains almost unchanged after the lapse of at least twelve hours.
When the content of manganese is large the solution may be divided into two equal portions, one of which is first to be roughly titrated to ascertain its content approximately, after which the whole is to be mixed together and the titration completed, which can thus be performed with greater speed and certainty. If too much chameleon has been added, one may titrate back with an accurately estimated solution of manganese, which is prepared most easily by evaporating fifteen cubic centimeters chameleon solution down to two or three cubic centimeters, boiling with two to three cubic centimeters hydrochloric acid so long as the smell of chlorine is observed, and then diluting the solution to ten cubic centimeters, when one cubic centimeter of it corresponds to the same measure of chameleon.
With respect to the delay which must take place during the titration in order to give the precipitate time to fall, it is advantageous, in order to save time, to work with several samples; but it is, in such a case, desirable to have a separate burette for each sample, in order to avoid noting every addition of the chameleon solution and afterward adding them up. If burettes are wanting, and one must be used for several samples, a Mohr's burette with glass cock is the most convenient to use. For the titration of iron with chameleon solution, the latter is commonly used of such a strength that 0.01 gramme of iron corresponds to about one cubic centimeter of chameleon solution, which is obtained by dissolving 5.75 grammes permanganate of potash in 1,000 cubic centimeters water. The titration is determined by means of iron, a salt of iron or oxalic acid. A drop of such a solution, corresponding to about one-twentieth cubic centimeter, or 0.0001 gramme Mn, is sufficient to give a perceptible reddish color to 200 cubic centimeters of water.
As what takes place in the titration of iron with chameleon is indicated by the following formula,
10FeO + 2KMnO_{4} = 5Fe_{2}O_{3} + K_{2}O + 2MnO_{2},
it appears, on making a comparison with the formula given above, that ten equivalents of iron correspond to three equivalents of manganese, and that there is thus required for three equivalents manganese as much chameleon solution as for ten equivalents iron. When we know the titration of the chameleon solution for iron, that for manganese is obtained by multiplying the former by (3 x 55)/(10 x 56) =0.295. If, for instance, one cubic centimeter chameleon solution corresponds to 0.01 gramme iron, the figure for manganese is 0.01 x 0.295 = 0.00295 gramme per cubic centimeter.
We can of course also determine the titration for manganese in a chameleon solution with the greatest certainty by titrating a compound of manganese with an accurately estimated content of it, for instance, a spiegeleisen or ferromanganese; the test is carried out in the following way: The substance, which is to be examined for manganese, is dissolved by means of hydrochloric acid. If the manganese, as in slags, be combined with silica, it is frequently necessary first to fuse the specimen with soda. Iron ores and refinery cinders may indeed, if they are reduced to a very fine state of division, be commonly decomposed by boiling with hydrochloric acid with or without the addition of sulphuric acid, but the undissolved silica is generally rendered impure by manganese, which can only be removed by fusion with soda.
The dissolving of the fused mass in hydrochloric acid does not need to be carried to dryness for the separation of the soluble silica, but the boiling, after the addition of a little nitric acid, is only kept up until the iron passes into perchloride and the manganese into protochloride. The quantity, which ought to be taken for the test, depends on the accuracy with which it is desired to have the manganese estimated.
Of ferromanganese and other very manganiferous substances, in which the manganese need not be determined with greater exactness than to 0.1 per cent., only 0.01 gram. is taken for a test; but of common pig, wrought iron, steel, iron ore, slags, etc., there is taken 0.5 to 1 gramme according to the supposed content of manganese and the desired exactness of the estimation. For instance one gramme iron, which has passed through a metal sieve with holes half a millimeter in diameter, is placed in a beaker 125 mm. in height and 60 mm. in diameter, and has added to it twenty cubic centimeters of hydrochloric acid of 1.12 specific gravity, which, with a well-fitting glass cover, is boiled for half an hour, in order that the combined carbon may be driven off in the shape of gas. After at least the half of the hydrochloric acid has been boiled away, there are added at least five cubic centimeters nitric acid of 1.2 specific gravity, partly to bring the iron to peroxide, partly to destroy the organic matters formed from the carbon, which might possibly be remaining and might tend to remove the color of the chameleon solution. The boiling is now continued till near dryness, when five cubic centimeters hydrochloric acid are added, after which the solution is boiled as long as any reddish-yellow vapors of nitrous acid are observed. When these have disappeared a drop of the liquid taken up on a small glass rod is tested with an newly prepared solution of red prussiate of potash (2 grammes in 100 cubic centimeters water), to ascertain whether there is any protoxide of iron remaining. First, when no indication of blue or green is visible, the test shows a pure yellow, it is certain that there are no reducing substances in the solution.
If a trace of protoxide of iron remains in the solution another cubic centimeter of nitric acid ought to be added and the boiling continued so long as any reddish-yellow vapors are visible, more hydrochloric acid also being added to keep the solution from being dried up. The process is continued in this way until two tests have given no reaction of protoxide of iron, when the solution is diluted with water; but no dilution should take place until the oxidation is complete, because in the course of it the solution ought to be kept as concentrated as possible. Silica, and graphite when it is present, need not be removed by filtration, if it is not intended to estimate them, or there be no fear that the graphite is accompanied by any humous substance, or that any oily, viscous compound has been deposited on the sides of the beaker. In the last mentioned case the solution should be transferred into another beaker, and filtered, if graphite be present. When the solution is evaporated to dryness, the remainder has five cubic centimeters hydrochloric acid added to it, and the liquid is then brought to boiling in order that the perchloride of manganese possibly formed during the evaporation to dryness may be reduced to protochloride, after which the solution is diluted with water till it measures about 100 cubic centimeters. To this is now added in small portions and with constant stirring as much of a saturated solution of bicarbonate of soda (thirteen parts water dissolve one part salt), that all the iron is precipitated, after which, when the escape of carbonic acid has ceased, the solution is diluted with water till it measures 200 cubic centimeters and is then ready for titration.
A large excess of bicarbonate ought to be avoided, because in a solution of pure protochloride of manganese it renders the liquid milky and turbid; the addition of more water, however, makes it clear. The solution of bicarbonate must be free from organic substances which may tend to remove the color of the chameleon solution. To ascertain this, the latter is added to the former drop by drop so long as the color is removed.
If it be desired to estimate the silica in the same test, the iron, as when it is analyzed for silica, may be also dissolved in sulphuric acid, and afterward oxidized with nitric acid, after which the solution is boiled to near dryness, so that the organic substances are completely destroyed. In order afterward, to drive off the nitric acid and get the manganese with certainty reduced to protoxide, the solution is boiled with a little hydrochloric acid. In this way the solution goes on rapidly and conveniently, but the titration takes longer time than when the iron is dissolved in hydrochloric acid, because the iron precipitate is more voluminous, and, in consequence, longer in being deposited. To diminish this inconvenience the solution ought to be made larger. In such a case the rule for dissolving is, one gramme iron (more if the content of silica is small) is dissolved in a mixture of two cubic centimeters sulphuric acid of 1.83 specific gravity and twelve cubic centimeters of water in the way described above, and boiled until salt of iron begins to be deposited on the bottom of the beaker. Five cubic centimeters hydrochloric acid are now added, and the solution tested with red prussiate of potash for protoxide of iron, and the boiling continued till near dryness, when all the nitric acid is commonly driven off. Should nitrous acid still show itself, some more hydrochloric acid is added and the boiling continued.
As in dissolving in hydrochloric acid and oxidizing with nitric acid the solution ought to be twice tested for protoxide of iron, even although at the first test none can be discovered. The silica is taken upon a filter, dried, ignited, and weighed. The filtrate is treated with bicarbonate of soda, and titrated with chameleon solution in the way described above. If the content of manganese is small (under 0.5 per cent.) it is not necessary to warm the liquid before titration; but in proportion as the content of manganese is larger there is so much greater reason to hasten the removal of color by warming and constant stirring toward the close of the titration.
* * * * *
ON THE ESTIMATION AND SEPARATION OF MANGANESE.
[Footnote: Read before the American Chemical Society, Dec. 16, 1881]
By NELSON H. DARTON.
The element manganese having many peculiarities in its reactions with the other elements, is now extensively used in the arts, its combinations entering into and are used in many of the important processes; it is consequently often brought before the chemist in his analysis, and has to be determined in most cases with considerable accuracy. Many methods have been proposed for this, all of them of more or less value; those yielding the best results, however, requiring a considerable length of time for their execution, and involving so large an amount of manipulatory skill as to render them fairly impracticable to a chemist at all pressed for time, and receiving but a mere trifle for the results.
As I have had to make numerous estimations of manganese in various compounds, as a public analyst, I have been induced to investigate the volumetric methods at present in use to find their comparative values, and if possible to work out a new one, setting aside one or more of the difficulties met with in the use of the older ones. This paper is a part summary of the results. First, I will detail my process of estimation, then on the separation.
From all compounds of manganese, excepting those containing cobalt and nickel, the manganese is precipitated as binoxide; those containing these two elements are treated with phosphoric acid, or as noted under Separation.
A.—The Estimation. The binoxide of commerce, as taken from the mine, is well sampled, powdered, and dried at 100 deg.C. 0.5 gramme of this is taken and placed in a 250 c.c. flask; in analysis the binoxide on the filter, from the treatments noted under separation is thoroughly washed with warm water; it is then washed down in a flask, as above, after breaking the filter paper; sufficient water is added to one-third fill the flask, and about twice the approximate weight of the binoxide in the flask of oxalate of potassa; these are agitated together. A twice perforated stopper is fitted to this flask, carrying through one opening a 25 c c. pipette nearly filled with sulphuric acid, sp. gr. 1.4, the lower point of which just dips below the mixture in the flask, and the upper end, carrying a rubber tube and pinch cock to control the flow of acid. Through the other opening passes a glass tube bent at an acute angle and connected by a short rubber tube to an adjoining flask, two-thirds filled with decinormal baryta solutions. These connections are all made air tight. Sulphuric acid is allowed in small portions at a time to flow into the mixture. Carbonic acid is evolved, and, passing into the adjoining flask, is absorbed by the baryta, precipitating it as carbonate. To prevent the precipitate forming around or choking up the entrance tube, the flask must be agitated at short intervals to break it off. The reaction so familiar to us in other determinations is expressed thus:
MnO_{2}+KO,C_{2}O_{3}+2SO_{3} = MnO,SO_{3}+KO.SO_{3}+2CO_{2},
When no more carbonic acid is evolved, another tube from this last flask is connected with the aspirator, the pinch-cock of the pipette open, and air drawn through the apparatus for about half a minute, and thus all the carbonic acid evolved absorbed, or the flasks may be slightly heated. If danger of more carbonic acid being absorbed from the air is feared, and always in very accurate analysis, a potassa tube may be connected to the pipette before drawing the air through. The precipitate formed is allowed to settle, 50 c.c. of the supernatant solution is removed with a pipette and transferred to a beaker; 50 c.c. of decinormal nitric acid and some water is added with sufficient cochineal tincture. It is then titrated back with decinormal soda; from this is now readily deducted the amount of carbonic acid, and from that the MnO_{2}, holding in view that 44 parts of carbonic acid is equivalent to 43.5 of MnO_{2} or 98.87 per cent, and that 1 c.c. of the N/10 baryta solution is equivalent to 0.0022 grm. of CO_{2}.
If a carbonate, chloride, or nitrate, be present in the native binoxide, it must be removed with some sulphuric acid. This is afterward neutralized with a little caustic soda. This method yields the following results for its value in amount of manganese to 100: 99.91-99.902-99.895, and can be executed in about twenty minutes. Fifteen determinations can be carried on at once without loss of time, this, however, depending on the operator's skill. I have made many assays, and assays by this method with similarly excellent results.
Of the other methods, Bunsen's is acknowledged to be the most accurate, but is, of course, too troublesome to be used in technical work, although it is used in scientific analysis. Ordinary samples are not sufficiently accurate to allow the use of this method.
The methods of reducing with iron and titrating this with chromate of potassa, etc., have given a constant average of from 98.60-99.01. These results are fair, but hard to obtain expeditiously.
Of the methods of precipitating the compounds of the protoxide and estimating the acid, that of the phosphate is by far the most accurate, titrating with uranium solution; 99.82 is a nearly constant average with me, much depending on the operator's familiarity with the uranium process.
The methods of Lenssen, or ferricyanide of potassium method, yields very widely differing results. I have found the figures of Fresenius about the same as my own in this case; that is from 98.00-100.10.
B.—On the Separation. First, from its soluble simple combinations with the acids or bases containing no iron or cobalt; if they are present, it is treated as is noted later. If sulphuric acid is present it must be separated by treating the solution of the compound with barium chloride and filtering. A nearly neutral solution is prepared in water or hydrochloric acid and placed in a flask. Here it is treated with chlorine by passing a current of that gas through it as long as it causes a precipitate and for some time afterward. It is then discontinued, the mixture allowed to deposit for a few moments, and about two-thirds of the supernatant solution decanted; it is mixed with some more water, and these decantations repeated until they pass away without reaction, or by filtering it and washing on the filter; it is then dissolved in hot hydrochloric acid, this nearly neutralized, a solution of sesquichloride of iron is added, and again treated with an excess of chlorine. After washing it is transferred to the flasks of the apparatus mentioned in the first part of this paper, and estimated. Myself and several others have found this always to be a true MnO_{2}, and not a varying mixture of protosesquioxide and binoxide, and will thus yield accurate results. This reprecipitation may sometimes be dispensed with by adding the iron salt before the first precipitation, but it of course depends upon the other elements present.
From Compounds containing Cobalt, Cobalt and Nickel, Iron and group III., together or with other elements.—Group III. and sesqui. iron are separated by agitation with baryta carbonate, some chloride of ammonia being added to prevent nickel and cobalt precipitation traces, and filtering. If cobalt is present we treat this filtrate with nitrite of potassa, etc., to separate it (that is, if it and nickel are to be separated and estimated in the same sample; but if they are to be estimated as one, or not separated, the treatment with nitrite, etc., is not used). The filtrate from this last is directly treated with chlorine. If nickel and cobalt are not to be estimated in this sample, the solution, as chlorides, is mixed with some chloride of ammonium and ammonia, then with a fair excess of phosphoric acid, a sufficient quantity more of ammonia to render the mixture alkaline. The precipitate formed is transferred to the filter and well washed with water containing NH{3}Cl and NH{4}O, then dissolved in hydrochloric acid and reprecipitated with ammonia, filtering and washing as before. It is again dissolved in HCl and titrated with uranium solution, or decomposed by tin, as noted below, and the manganese precipitated as binoxide with chlorine, and determined. The latter method is hardly practicable, and I never have time to use it, as the titration and all together yields a value of 99.80 in most cases, if accurately executed.
From the bases of groups V. and VI. these are separated by hydrogen sulphide, from iron in alloys, ores, etc., and in general the iron is separated as basic acetate, and the manganese afterward precipitated with chlorine. Bromine is generally used in place of chlorine, the use of which chemists claim as troublesome; but in a number of examinations I have found it to yield more satisfactory results than bromine, which is much more expensive.
From the acids in insoluble and a few other compounds, chromic, arsenic, and arsenious acids, by fusion with carbonate of soda in presence of carbonic acid gas; borate of manganese is readily decomposed when the boracic acid is to be determined by boiling with solution of potassa, dissolving the residue in hydrochloric acid and precipitating the manganese as binoxide. This boiling, however, is seldom needed, as the borate is soluble in HCl.
From phosphoric acid I always use Girard's method of treatment with tin, using it rasped, and it yields much more accurate results with but little manipulation. When the other acids mentioned above are present in the compound, we treat it as directed there.
From silicic acid, by evaporation with hydrochloric acid.
From sulphur or iodine, by decomposing with sulphuric acid and separating this with baryta chloride.
* * * * *
RESEARCHES ON ANIMALS CONTAINING CHLOROPHYL.
[Footnote: Abstract of a paper "On the Nature and Functions of the 'Yellow Cells' of Radiolarians and Coelenterates," read to the Royal Society of Edinburgh, on January 14, 1882, and published by permission of the Council.—Nature.]
It is now nearly forty years since the presence of chlorophyl in certain species of planarian worms was recognized by Schultze. Later observers concluded that the green color of certain infusorians, of the common fresh water hydra and of the fresh water sponge, was due to the same pigment, but little more attention was paid to the subject until 1870, when Ray Lankester applied the spectroscope to its investigation. He thus considerably extended the list of chlorophyl containing animals, and his results are summarized in Sachs' Botany (Eng. ed.). His list includes, besides the animals already mentioned, two species of Radiolarians, the common green sea anemone (Anthea cereus, var. Smaragdina), the remarkable Gephyrean, Bonellia viridis, a Polychaete worm, Chaetoperus, and even a Crustacean, Idotea viridis.
The main interest of the question of course lies in its bearing on the long-disputed relations between plants and animals; for, since neither locomotion nor irritability is peculiar to animals; since many insectivorous plants habitually digest solid food; since cellulose, that most characteristic of vegetable products, is practically identical with the tunicin of Ascidians, it becomes of the greatest interest to know whether the chlorophyl of animals preserves its ordinary vegetable function of effecting or aiding the decomposition of carbonic anhydride and the synthetic production of starch. For although it had long been known that Euglena evolved oxygen in sunlight, the animal nature of such an organism was merely thereby rendered more doubtful than ever. In 1878 I had the good fortune to find at Roscoff the material for the solution of the problem in the grass-green planarian, Convoluta schultzii, of which multitudes are to be found in certain localities on the coast, lying on the sand, covered only by an inch or two of water, and apparently basking in the sun. It was only necessary to expose a quantity of these animals to direct sunlight to observe the rapid evolution of bubbles of gas, which, when collected and analyzed, yielded from 45 to 55 per cent. of oxygen. Both chemical and histological observations showed the abundant presence of starch in the green cells, and thus these planarians, and presumably also Hydra spongilla, etc., were proved to be truly "vegetating animals."
Being at Naples early in the spring of 1879, I exposed to sunlight some of the reputedly chlorophyl containing animals to be obtained there, namely, Bonellia viridis and Idotea viridis, while Krukenberg had meanwhile been making the same experiment with Bonellia and Anthea at Trieste. Our results were totally negative, but so far as Bonellia was concerned this was not to be wondered at since the later spectroscopic investigations of Sorby and Schenk had fully confirmed the opinion of Lacaze-Duthiers as to the complete distinctness of its pigment from chlorophyl. Krukenberg, too, who follows these investigators in terming it bonellein, has recently figured the spectra of Anthea-green, and this also seems to differ considerably from chlorophyl, while I am strongly of the opinion that the pigment of the green crustaceans is, if possible, even more distinct, having not improbably a merely protective resemblance.
It is now necessary to pass to the discussion of a widely distinct subject—the long outstanding enigma of the nature and functions of the "yellow cells" of Radiolarians. These bodies were first so called by Huxley in his description of Thallassicolla, and are small bodies of distinctly cellular nature, with a cell wall, well defined nucleus, and protoplasmic contents saturated by a yellow pigment. They multiply rapidly by transverse division, and are present in almost all Radiolarians, but in very variable number. Johnnes Muller at first supposed them to be concerned with reproduction, but afterward gave up this view. In his famous monograph of the Radiolarians, Haeckel suggests that they are probably secreting cells or digestive glands in the simplest form, and compares them to the liver-cells of Amphioxus, and the "liver-cells" described by Vogt in Velella and Porpita. Later he made the remarkable discovery that starch was present in notable quantity in these yellow cells, and considered this as confirming his view that these cells were in some way related to the function of nutrition. In 1871 a very remarkable contribution to our knowledge of the Radiolarians was published by Cienkowski, who strongly expressed the opinion that these yellow cells were parasitic algae, pointing out that our only evidence of their Radiolarian nature was furnished by their constant occurrence in most members of the group. He showed that they were capable not only of surviving the death of the Radiolarian, but even of multipying, and of passing through an encysted and an amoeboid state, and urged their mode of development and the great variability of their numbers within the same species as further evidence of his view.
The next important work was that of Richard Hertwig, who inclined to think that these cells sometimes developed from the protoplasm of the Radiolarian, and failing to verify the observations of Cienkowski, maintained the opinion of Haeckel that the yellow cells "fur den Stoffwechsel der Radiolarien von Bedeutung sind." In a later publication (1879) he, however, hesitates to decide as to the nature of the yellow cells, but suggests two considerations as favoring the view of their parasitic nature—first, that yellow cells are to be found in Radiolarians which possess only a single nucleus, and secondly, that they are absent in a good many species altogether.
A later investigator, Dr. Brandt, of Berlin, although failing to confirm Haeckel's observations as to the presence of starch, has completely corroborated the main discovery of Cienkowski, since he finds the yellow cells to survive for no less than two months after the death of the Radiolarian, and even to continue to live in the gelatinous investment from which the protoplasm had long departed in the form of swarm-spores. He sum up the evidence strongly in favor of their parasitic nature.
Meanwhile similar bodies were being described by the investigators of other groups. Haeckel had already compared the yellow cells of Radiolarians to the so-called liver-cells of Velella; but the brothers Hertwig first recalled attention to the subject in 1879 by expressing their opinion that the well-known "pigment bodies" which occur in the endoderm cells of the tentacles of many sea-anemones were also parasitic algae. This opinion was founded on their occasional occurrence outside the body of the anemone, on their irregular distribution in various species, and on their resemblance to the yellow cells of Radiolarians. But they did not succeed in demonstrating the presence of starch, cellulose, or chlorophyl. The last of this long series of researches is that of Hamann (1881), who investigates the similar structures which occur in the oral region of the Rhizostome jelly-fishes. While agreeing with Cienkowski as to the parasitic nature of the yellow cells of Radiolarians, he holds strongly that those of anemones and jelly-fishes are unicellular glands.
In the hope of clearing up these contradictions, I returned to Naples in October last, and first convinced myself of the accuracy of the observation of Cienkowski and Brandt as to the survival of the yellow cells in the bodies of dead Radiolarians, and their assumption of the encysted and the amoeboid states. Their mode of division, too, is thoroughly algoid. One finds, not unfrequently, groups of three and four closely resembling Protococcus. Starch is invariably present; the wall is true plant-cellulose, yielding a magnificent blue with iodine and sulphuric acid, and the yellow coloring matter is identical with that of diatoms, and yields the same greenish residue after treatment with alcohol. So, too, in Velella, in sea-anemones, and in medusae; in all cases the protoplasm and nucleus, the cellulose, starch, and chlorophyl, can be made out in the most perfectly distinct way. The failure of former observers with these reactions, in which I at first also shared, has been simply due to neglect of the ordinary botanical precautions. Such reactions will not succeed until the animal tissue has been treated with alcohol and macerated for some hours in a weak solution of caustic potash. Then, after neutralizing the alkali by means of dilute acetic acid, and adding a weak solution of iodine, followed by strong sulphuric acid, the presence of starch and cellulose can be successively demonstrated. Thus, then, the chemical composition, as well as the structure and mode of division of these yellow cells, are those of unicellular algae, and I accordingly propose the generic name of Philozoon, and distinguish four species, differing slightly in size, color, mode of division, behavior with reagents, etc., for which the name of P. radiolarum, P. siphonophorum, P. actiniarum, and P. medusarum, according to their habitat, may be conveniently adopted. It now remains to inquire what is their mode of life, and what their function.
I next exposed a quantity of Radiolarians (chiefly Collozoum) to sunshine, and was delighted to find them soon studded with tiny gas-bubbles. Though it was not possible to obtain enough for a quantitative analysis, I was able to satisfy myself that the gas was not absorbed by caustic potash, but was partly taken up by pyrogallic acid, that is to say, that little or no carbonic acid was present, but that a fair amount of oxygen was present, diluted of course by nitrogen. The exposure of a shoal of the beautiful blue pelagic Siphonophore, Velella, for a few hours, enabled me to collect a large quantity of gas, which yielded from 24 to 25 per cent. of oxygen, that subsequently squeezed out from the interior of the chambered cartilaginous float, giving only 5 per cent. But the most startling result was obtained by the exposure of the common Anthea cereus, which yielded great quantities of gas containing on an average from 32 to 38 per cent. of oxygen.
At first sight it might seem impossible to reconcile this copious evolution of oxygen with the completely negative results obtained from the same animal by so careful an experimenter as Krukenberg, yet the difficulty is more apparent than real. After considerable difficulty I was able to obtain a large and beautiful specimen of Anthea cereus, var. smaragdina, which is a far more beautiful green than that with which I had been before operating—the dingy brownish-olive variety, plumosa. The former owes its color to a green pigment diffused chiefly through the ectoderm, but has comparatively few algae in its endoderm; while in the latter the pigment is present in much smaller quantity; but the endoderm cells are crowded by algae. An ordinary specimen of plumosa was also taken, and the two were placed in similar vessels side by side, and exposed to full sunshine; by afternoon the specimen of plumosa had yielded gas enough for an analysis, while the larger and finer smaragdina had scarcely produced a bubble. Two varieties of Ceriactis aurantiaca, one with, the other without, yellow cells, were next exposed, with a precisely similar result. The complete dependence of the evolution of oxygen upon the presence of algae, and its complete independence of the pigment proper to the animal, were still further demonstrated by exposing as many as possible of those anemones known to contain yellow cells (Aiptasia chamaeleon, Helianthus troglodytes, etc.) side by side with a large number of forms from which these are absent (Actinia mesembryanthemum, Sagastia parasitica, Cerianthus, etc.). The former never failed to yield abundant gas rich in oxygen, while in the latter series not a single bubble ever appeared.
Thus, then, the coloring matter described as chlorophyl by Lankester has really been mainly derived from that of the endodermal algae of the variety plumosa, which predominates at Naples; while the anthea-green of Krukenberg must mainly consist of the green pigment of the ectoderm, since the Trieste variety evidently does not contain algae in any great quantity. But since the Naples variety contains a certain amount of ordinary green pigment, and since the Trieste variety is tolerably sure to contain some algae, both spectroscopists have been operating on a mixture of two wholly distinct pigments—diatom-yellow and anthea-green.
But what is the physiological relationship of the plants and animal thus so curiously and intimately associated? Every one knows that all the colorless cells of a plant share the starch formed by the green cells; and it seems impossible to doubt that the endoderm cell or the Radiolarian, which actually incloses the vegetable cell, must similarly profit by its labors. In other words, when the vegetable cell dissolves its own starch, some must needs pass out by osmose into the surrounding animal cell; nor must it be forgotten that the latter possesses abundance of amylolytic ferment. Then, too, the Philozoon is subservient in another way to the nutritive function of the animal, for after its short life it dies and is digested; the yellow bodies supposed by various observers to be developing cells being nothing but dead algae in progress of solution and disappearance.
Again, the animal cell is constantly producing carbonic acid and nitrogenous waste, but these are the first necessities of life to our alga, which removes them, so performing an intracellular renal function, and of course reaping an abundant reward, as its rapid rate of multiplication shows.
Nor do the services of the Philozoon end here; for during sunlight it is constantly evolving nascent oxygen directly into the surrounding animal protoplasm, and thus we have actually foreign chlorophyl performing the respiratory function of native haemoglobin! And the resemblance becomes closer when we bear in mind that haemoglobin sometimes lies as a stationary deposit in certain tissues, like the tongue muscles of certain mollusks, or the nerve cord of Aphrodite and Nemerteans.
The importance of this respiratory function is best seen by comparing as specimens the common red and white Gorgonia, which are usually considered as being mere varieties of the same species, G. verrucosa. The red variety is absolutely free from Philozoon, which could not exist in such deeply colored light, while the white variety, which I am inclined to think is usually the larger and better grown of the two, is perfectly crammed. Just as with the anemones above referred to, the red variety evolves no oxygen in sunlight, while the white yields an abundance, and we have thus two widely contrasted physiological varieties, as I may call them, without the least morphological difference. The white specimen, placed in spirit, yields a strong solution of chlorophyl; the red, again, yields a red solution, which was at once recognized as being tetronerythrin by my friend M. Merejkowsky, who was at the same time investigating the distribution and properties of that remarkable pigment, so widely distributed in the animal kingdom. This substance, which was first discovered in the red spots which decorate the heads of certain birds, has recently been shown by Krukenberg to be one of the most important of the coloring matter of sponges, while Merejkowsky now finds it in fishes and in almost all classes of invertebrate animals. It has been strongly suspected to be an oxygen-carrying pigment, an idea to which the present observation seems to me to yield considerable support. It is moreover readily bleached by light, another analogy to chlorophyl, as we know from Pringsheim's researches.
When one exposes an aquarium full of Anthea to sunlight, the creatures, hitherto almost motionless, begin to wave their arms, as if pleasantly stimulated by the oxygen which is being developed in their tissues. Specimens which I kept exposed to direct sunshine for days together in a shallow vessel placed on a white slab, soon acquired a dark, unhealthy hue, as if being oxygenated too rapidly, although I protected them from any undue rise of temperature by keeping up a flow of cold water. So, too, I found that Radiolarians were killed by a day's exposure to sunshine, even in cool water, and it is to the need for escaping this too rapid oxidation that I ascribe their remarkable habit of leaving the surface and sinking into deep water early in the day.
It is easy, too, to obtain direct proof of this absorption of a great part of the evolved oxygen by the animal tissues through which it has to pass. The gas evolved by a green alga (Ulva) in sunlight may contain as much as 70 per cent. of oxygen, that evolved by brown algae (Haliseris) 45 per cent., that from diatoms about 42 per cent.; that, however, obtained from the animals containing Philozoon yielded a very much lower percentage of oxygen, e.g. Velella 24 per cent., white Gorgonia 24 per cent., Ceriactis 21 per cent., while Anthea, which contains most algae, gave from 32 to 38 per cent. This difference is naturally to be accounted for by the avidity for oxygen of the animal cells.
Thus, then, for a vegetable cell no more ideal existence can be imagined than that within the body of an animal cell of sufficient active vitality to manure it with carbonic acid and nitrogen waste, yet of sufficient transparency to allow the free entrance of the necessary light. And conversely, for an animal cell there can be no more ideal existence than to contain a vegetable cell, constantly removing its waste products, supplying it with oxygen and starch, and being digestible after death. For our present knowledge of the power of intracellular digestion possessed by the endoderm cells of the lower invertebrates removes all difficulties both as to the mode of entrance of the algae, and its fate when dead. In short, we have here the relation of the animal and the vegetable world reduced to the simplest and closest conceivable form.
It must be by this time sufficiently obvious that this remarkable association of plant and animal is by no means to be termed a case of parasitism. If so, the animals so infested would be weakened, whereas their exceptional success in the struggle for existence is evident. Anthea cereus, which contains most algae, probably far outnumbers all the other species of sea-anemones put together, and the Radiolarians which contain yellow cells are far more abundant than those which are destitute of them. So, too, the young gonophores of Velella, which bud off from the parent colony and start in life with a provision of Philozoon (far better than a yolk-sac) survive a fortnight or more in a small bottle—far longer than the other small pelagic animals. Such instances, which might easily be multiplied, show that the association is beneficial to the animals concerned.
The nearest analogue to this remarkable partnership is to be found in the vegetable kingdom, where, as the researches of Schwendener, Bornet, and Stahl have shown, we have certain algae and fungi associating themselves into the colonies we are accustomed to call lichens, so that we may not unfairly call our agricultural Radiolarians and anemones animal lichens. And if there be any parasitism in the matter, it is by no means of the alga upon the animal, but of the animal, like the fungus, upon the alga. Such an association is far more complex than that of the fungus and alga in the lichen, and indeed stands unique in physiology as the highest development, not of parasitism, but of the reciprocity between the animal and vegetable kingdoms. Thus, then, the list of supposed chlorophyl containing animals with which we started, breaks up into three categories; first those which do not contain chlorophyl at all, but green pigments of unknown function (Bonelia<, Idotea, etc.); secondly, those vegetating by their own intrinsic chlorophyl (Convoluta, Hydra, Spongilia); thirdly, those vegetating by proxy, if one may so speak, rearing copious algae in their own tissues, and profiting in every way by the vital activities of these.
PATRICK GEDDES.
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COMPRESSED OIL GAS FOR LIGHTING CARS, STEAMBOATS, AND BUOYS.
We give in the accompanying figures the arrangement of the different apparatus necessary for the manufacture and compression of illuminating gas on the system of Mr. Pintsch, as well as the arrangements adopted by the inventor for the lighting of railway cars and buoys. This system has been adopted to some extent in both Germany and England, and is also being introduced into France.
The Pintsch gas is prepared by the distillation of heavy oils in a furnace composed of two superposed retorts. The oil to be volatilized is contained in a vertical reservoir B, which carries a bent pipe that enters the upper retort, A. The flow of the oil is regulated in this conduit by means of a micrometer screw which permits of varying the supply according to the temperature of the retorts. In order to facilitate the vaporization, the flow of oil starts from a cast-iron trough, C, and from thence spreads in a thin and uniform layer in the retort. The residua of distillation remain almost entirely in the reservoir, O, from whence they are easily removed. The vapor from the oil which is disengaged in the vessel, A, goes to the lower retort, D, in which the transformation of the matter is thoroughly completed. On leaving the latter, the gas enters the drum, E, at the lower part of the furnace. To prevent the choking up of the pipe, R, the latter is provided with a joint permitting of dilatation. The gas on leaving E goes to the condenser, G G, where it is freed from its tar. The latter flows out, and the gas proceeds to the washer, J, and the purifiers, I and I, to be purified. The amount of production is registered by the meter, L.
When the gas is to be utilized for lighting railway cars or buoys, it is compressed in the accumulators, T, which are large cylindrical reservoirs of riveted or welded iron plate.
Compression is effected by means of a pump, F or F', which sucks the gas into a desiccating cylinder, M, connected with the gasometer of the works The pump, F, which is used when the production is larger than usual, has two compressing cylinders of different diameters, one measuring 170 millimeters and the other 100. The piston has a stroke of 320 millimeters. The two compressing cylinders are double acting, and communicate with each other by valves so arranged as to prevent injurious spaces. The gas drawn from the gasometer is first compressed in the larger cylinder to a pressure of about 4 atmospheres; then it passes into the second cylinder, whence it is forced into the accumulators under a pressure varying from 10 to 12 atmospheres. |
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