Finally, the somnambulistic condition proceeds from catalepsy or from lethargy by means of a slight pressure upon the vertex, and is particularly sensitive to every psychical influence. In some subjects the eyes are open, in others closed. Here, also, a slight irritation produces a certain amount of rigor in the muscle that has been touched, but it does not weaken the antagonistic muscle, as in lethargy, nor does it vanish under the influence of the same excitement that has produced it. In order to put an end to the somnambulistic condition, one must press softly upon the pupil of the eye, upon which the subject becomes lethargic, and is easily roused by breathing upon him. In this early stage, somnambulism appears very infrequently.

Charcot's school also recognize the existence of compound conditions, the history of whose symptoms we must not follow here. These slightly sketched results, as well as a number of other facts, were only obtained in the course of several years; yet in 1882 the fundamental investigations of this school were considered virtually concluded. Then Dumont-Pallier, the head of the Parisian Hospital Pitie, came forward with a number of observations, drawn also exclusively from the study of hystero-hypnotism, and yet differing widely from those reached by the physicians of the Salpetriere. In a long series of communications, he has given his views, which have in their turn been violently attacked, especially by Magnin and Berillon. I give only the most important points.

According to these men, the hyper-excitability of the nerves and muscles is present not only in the lethargic condition, but in all three periods; and in order to prove this, we need only apply the suitable remedy, which must be changed for each period and every subject. Slight irritations of the skin prove this most powerfully. A drop of warm water or a ray of sunshine produces contractions of a muscle whose skin covering they touch.

Dumont-Pallier and Magnin accede to the theory of intermediate stages, and have tried to lay down rules for them with as great exactness as Charcot's school. They also are very decided about the three periods, whose succession does not appear to them as fixed; but they discovered a new fundamental law which regulates the production as well as the cessation of the condition—La cause qui fait, defait; that is, the stimulus which produces one of the three periods needs only to be repeated in order to do away with that condition. From this the following diagram of hypnotic conditions is evolved:



And, furthermore, Dumont-Pallier should be considered as the founder of a series of experiments, for he was the first one to show in a decisive manner that the duality of the cerebral system was proved by these hypnotic phenomena; and his works, as well as those of Messrs. Berillon and Descourtis, have brought to light the following facts: Under hypnotic conditions, the psychical activity of a brain hemisphere may be suppressed without nullifying the intellectual activity or consciousness. Both hemispheres may be started at the same time in different degrees of activity; and also, when the grade is the same, they may be independently the seat of psychical manifestations which are in their natures entirely different. In close connection with this and with the whole doctrine of hemi-hypnotism, which is founded upon these facts, stand the phenomena of thought transference, which we must consider later.

As an addition to the investigations of Charcot and Dumont-Pallier, Bremaud, in 1884, made the discovery that there was a fourth hypnotic state, "fascination," which preceded the three others, and manifested itself by a tendency to muscular contractions, as well as through sensitiveness to hallucination and suggestion, but at the same time left to the subject a full consciousness of his surroundings and remembrance of what had taken place. Descourtis, in addition, perceived a similar condition in the transition from hypnotic sleep to waking, which he called delire posthypnotique, and, instead of using the word "fascination" to express the opening stage, he substituted "captation." According to him, the diagram would be the following:



This whole movement, which I have tried to sketch, and whose chief peculiarity is that it considers hypnotism a nervous malady, and one that must be treated clinically and nosographically, was opposed in 1880 in two directions—one source of opposition producing great results, while the other fell to the ground. The latter joined itself to the theory of the mesmerists, and tried, by means of exact experiments, to measure the fluid emanating from the human body—an undertaking which gave slight promise of any satisfactory result.

Baillif in his thesis (1878) and Chevillard in his (for spiritualists) very interesting books, tried, by means of various arguments, to uphold the fluidic explanation. Despine also thought that by its help he had been able to explain the phenomena; but it was Barety who, in the year 1881, first turned general attention in this direction. According to him, mankind possesses a nerve force which emanates from him in different kinds of streams. Those coming from the eyes and fingers produce insensibility to pain, while those generated by the breath cause hypnotic conditions. This nerve force goes out into the ether, and there obeys the laws that govern light, being broken into spectra, etc.

Claude Perronnet has more lately advanced similar views, and his greatest work is now in press. Frederick W.H. Myers and Edmund Gurney sympathize with these views, and try to unite them with the mesmerist doctrine of personal influence and their theory of telepathy. The third champion in England of hypnotism, Prof. Hack Tuke, on the contrary, sympathizes entirely with the Parisian school, only differing from them in that he has experimented with satisfactory results upon healthy subjects. In France this view has lately been accepted by Dr. Bottey, who recognizes the three hypnotic stages in healthy persons, but has observed other phenomena in them, and vehemently opposes the conception of hypnotism as a malady. His excellently written book is particularly commended to those who wish to experiment in the same manner as the French investigator, without using hysterical subjects.

The second counter current that opposed itself to the French neuropathologists, and produced the most lasting impression, is expressed by the magic word "suggestion." A generation ago, Dr. Liebault, the patient investigator and skillful physician, had endeavored to make a remedial use of suggestion in his clinic at Nancy. Charles Richet and others have since referred to it, but Professor Bernheim was the first one to demonstrate its full significance in the realm of hypnotism. According to him, suggestion—that is, the influence of any idea, whether received through the senses or in a hypersensible manner (suggestion mentale)—is the key to all hypnotic phenomena. He has not been able in a single case to verify the bodily phenomena of grandehypnotisme without finding suggestion the primary cause, and on this account denies the truth of the asserted physical causes. Bernheim says that when the intense expectance of the subject has produced a compliant condition, a peculiar capacity is developed to change the idea that has been received into an action as well as a great acuteness of acceptation, which together will produce all those phenomena that we should call by the name of "pathological sleep," since they are only separable in a gradual way from the ordinary sleep and dream conditions. Bernheim is particularly strenuous that psychology should appear in the foreground of hypnotism, and on this point has been strongly upheld by men like Professors Beaunis and Richet.

The possibility of suggestion in waking conditions, and also a long time after the sleep has passed off (suggestions posthypnotiques ou suggestions a (longue) echeance), as well as the remarkable capacity of subjects to change their personality (changement de la personnalite objectivation des types), have been made the subject of careful investigation. The voluntary production of bleeding and stigmata through spiritual influence has been asserted, particularly by Messrs. Tocachon, Bourru, and Burot. The judicial significance of suggestion has been discussed by Professor Liegeois and Dr. Ladame. Professor Pitres in Bordeaux is one of the suggestionists, though differing in many points from the Nancy school.

This whole tendency brings into prominence the psychical influence, while it denies the production of these results from purely physical phenomena, endeavoring to explain them in a different manner. These explanations carry us into two realms, the first of which has been lately opened, and at present seems to abound more in enigmas than in solutions.

Metallotherapie, which was called into existence by Dr. Burg, and further extended by Dr. Gelle, contains a special point of interest—the so-called transference in the case of hysterically or hypnotically affected persons. Transference is caused by electro-magnetism, which has this peculiarity—that in the case of specially sensitive persons it can transfer the bodily affection from left to right, and vice versa. The transference of paralysis, the cures attempted on this plan, and the so-called "psychical transference," which contains special interest for graphologists, are at the present time still open questions, as well as the closely connected theory of human polarity; and the odic experiments of Dr. Chazarain are yet waiting for their confirmation. At present the problem of the connection between magnetism and hypnotism is under investigation, and in such a manner that we may hope for a speedy solution.

Still stranger than these reports are the accounts of the distant operation of certain bodies; at least, they seem strange to those unacquainted with psychometry and the literature of the past century relating to this subject. Two physicians in Rochefort, Professors Bourru and Burot, in treating a hystero-epileptic person, found that gold, even when at a distance of fifteen centimeters, produced in him a feeling of unbearable heat. They continued these experiments with great care, and, after a number of trials, came to this conclusion—that in some persons certain substances, even when carefully separated from them by long distance, exercise exactly the same physiological influence as if introduced into their organism. In order to explain these phenomena, they refer to the radiating force of Barety, an explanation neither satisfactory to themselves nor to others. Lately the distinguished Parisian physician, Dr. Luys, has confirmed by his experiments the existence of these phenomena, but he thinks the explanation referable to hyper-sensitiveness of the "regions emotives et intellectuelles de l'encephale" yet even he has not reached the kernel of the difficulty.

In close connection with action at a distance is the question of distant production of hypnotic sleep. For an answer to this problem, they are experimenting in both France and England; and Frederick W.H. Myers has thrown an entirely new light upon the subject by the investigations he is making upon a purely experimental basis. In Italy they have limited themselves to the study of isolated cases of hystero-hypnotism, except as the phenomena of magnetic fascination investigated by Donato have given rise to further research; but all the books I have seen upon this subject, as well as many by French authors, suffer from ignorance of the latest English discoveries.

With this I think that I have given a slight outline of the history of hypnotic investigation to the end of the year 1886. I shall attempt a criticism of this whole movement at some other time, as space is not afforded to me here; but I should like to make this statement now, that two of the characteristic indications of this period are of the gravest import—first the method ("Our work," says Richet, "is that of strictly scientific testing, observation, and arrangement"); and, secondly, the result. Hypnotism has been received into the realm of scientific investigation, and with this the foundation of a true experimental psychology has been laid.

MAX DESSOIR.

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THE DUODENUM: A SIPHON TRAP.

By MAYO COLLIER, M.S. Lond., F.R.C.S. Eng.; Senior Assistant Surgeon, North-West London Hospital; Assistant Demonstrator of Anatomy, London Hospital Medical College.

We may take it for granted that all gases generated in the jejunum, ileum, and large intestines pass onward toward the anus, and there sooner or later escape. Fetid gases—except those generated in the stomach and duodenum—never pass upward, not even during vomiting due to hernia, obstruction, and other causes. Physiologists, it would appear, have never busied themselves to find an explanation for this apparent breach of the laws of gravity. The intestinal canal is a tube with various dilatations and constrictions, but at no spot except the pylorus does the constriction completely obliterate the lumen of the tube, and here only periodically. It is perfectly evident, then, that, unless some system of trap exists in the canal, gases are free to travel from below upward in obedience to the laws of gravity, and would, as a matter of fact, sooner or later do so. From the straight, course and vertical position of the oesophagus, a very slight pressure of gas in the stomach easily overcomes the closure of its cardiac sphincter and allows of escape. When the stomach has digested its contents and the pylorus is relaxed, gases generated in the duodenum can and do ascend into the stomach and so escape. Normally, no fetid gases are generated in the stomach or duodenum. If we follow the course of the intestines down, we find that the duodenum presents a remarkable curve.

Now, there are some points of great interest in connection with this remarkable, almost circular, curve of the duodenum. In the first place, this curve is a constant feature in all mammalians. Mr. Treves says it is one of the most constant features in the anatomy of the intestines in man, and, speaking of mammalians in general, that the curve of the duodenum varies in shape, but is never absent, becoming more complex in some of the higher primates, but seldom less distinct than in man. In birds the duodenum always forms a long loop embracing the pancreas.

A second point of great interest is the absolute constancy and fixation of its terminal portion at the point of junction with the jejunum, more correctly termed second ascending or fourth portion. Mr. Treves says that this fourth portion is never less than an inch, and is practically constant. It extends along the side of the left crus of the diaphragm opposite the second lumbar vertebra, and is there firmly fixed to the front of the aorta and crus of the diaphragm by a strong fibro-muscular band, slinging it up and absolutely retaining it in position. This band has been termed the "musculus suspensorius duodeni," but is chiefly composed of white fibrous tissue, and is more of the native of a ligament than a muscle. This ligament is always present, and its position is never altered. The curve of the duodenum may descend as far as the iliac fossa, but the terminal portion is always maintained by this band in its normal position.

Another point of great constancy is the position of the pancreas and its relation to the curve of the duodenum. The duodenum always curves round the head of the pancreas and is, as it were, moulded on it and retained in position by it. In birds the duodenum always forms a long loop embracing the pancreas. Further, the ducts of the liver and pancreas always open into the center Of the duodenum, either separately or by a common opening.



Now, the absolute constancy of the curve of the duodenum, the complete fixation of its fourth portion, the position of the pancreas, and the place of entry of the ducts of the pancreas and liver, are all component parts of a siphon trap, whereby gases generated below the duodenum are prevented from passing upward. A reference to the accompanying diagrams will make this quite clear. A is a diagram of a siphon trap copied from Parkes' hygiene. B is a very diagrammatic outline of the stomach and duodenum, a is intended to mark the position of the fibrous band, or musculus suspensorius duodeni; and b the position of entry of the ducts of the liver and pancreas. The duodenum, then, is a siphon trap, and a most efficient one. Now, the efficiency of a siphon trap depends not only on its shape, but what is absolutely essential is that the curve must be kept constantly full of fluid, without which it ceases to be a trap, and would allow gases to ascend freely. The position of the place of entry of the ducts of the pancreas and liver assures that this sine qua non shall be present. The discharge of the secretions of the pancreas and liver, although more active during and after feeding, is practically constant, and so insures in an admirable manner that the curve on which the efficiency of the trap depends shall be constantly kept full not only with fluid, but, as I would suggest, antiseptic fluid. There is no other trap in the intestinal canal, but the peculiar position of the colon would no doubt have more or less effect in preventing gases ascending through the ileo-caecal valve.—Lancet.

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WISCONSIN CRANBERRY CULTURE.

Among the many thousands of well informed persons with whom the cranberry is a staple article of food throughout the autumn and winter, and who especially derive from its pungent flavor sharp relish for their Thanksgiving and Christmas turkey, not one in ten has any definite idea as to where the delicious fruit comes from, or of the method of growing and harvesting it. Most people are, however, aware that it is raised on little "truck patches" somewhere down in New Jersey or about Cape Cod, and some have heard that it is gleaned from the swamps in the Far West by Indians and shipped to market by white traders. But to the great majority its real history is unknown.

Yet the cranberry culture is an industry in which millions of dollars are invested in this country, and it gives employment, for at least a portion of each year, to many thousands of people. In the East, where the value of an acre of even swamp land may run up into the thousands of dollars, a cranberry marsh of five or ten acres is considered a large one, and, cultivated in the careful, frugal style in vogue there, may yield its owner a handsome yearly income. But in the great, boundless West, where land, and more especially swamp land, may be had for from $1 to $5 an acre, we do these things differently, if not better.

The State of Wisconsin produces nearly one-half of the cranberries annually grown in the United States. There are marshes there covering thousands of acres, whereon this fruit grows wild, having done so even as far back as the oldest tradition of the native red man extends. In many cases the land on which the berries grow has been bought from the government by individuals or firms, in vast tracts, and the growth of the fruit promoted and encouraged by a system of dikes and dams whereby the effects of droughts, frost, and heavy rainfalls are counteracted to almost any extent desired. Some of these holdings aggregate many thousands of acres under a single ownership; and after a marsh of this vast extent has been thoroughly ditched and good buildings, water works, etc., are erected on it, its value may reach many thousands of dollars, while the original cost of the land may have been merely nominal.

Large portions of Jackson, Wood, Monroe, Marinette, Juneau, and Green counties are natural cranberry marshes. The Wisconsin Valley division of the Chicago, Milwaukee & St. Paul Railway runs through a closely continuous marsh, forty miles long and nearly as wide, as level as a floor, which is an almost unbroken series of cranberry farms. The Indians, who inhabited this country before the white man came, used to congregate here every fall, many of them traveling several hundred miles, to lay in their winter supply of berries. Many thousands of barrels are now annually shipped from this region; and thus this vast area, which to the stranger looking upon it would appear utterly worthless, is as valuable as the richest farming lands in the State.

In a few instances, however, this fruit is cultivated in Wisconsin in a style similar to that practiced in the East; that is, by paring the natural sod from the bog, covering the earth to a depth of two or three inches with sand, and then transplanting the vines into soil thus prepared. The weeds are then kept down for a year or two, when the vines take full possession of the soil, and further attention is unnecessary. The natural "stand" of the vines in the sod is so productive, however, and the extent of country over which bountiful nature has distributed them so vast, that few operators have thought it necessary to incur the expense of special culture.

One of the best and most perfectly equipped marshes in Wisconsin is owned by Mr. G.B. Sackett, of Berlin. It is situated four miles north of that village, and comprises 1,600 acres, nearly all of which is a veritable bog, and is covered with a natural and luxuriant growth of cranberry vines. A canal has been cut from the Fox River to the southern limit of the marsh, a distance of 4,400 ft. It is 45 ft. wide, and the water stands in it to a depth of nine feet, sufficient to float fair sized steamboats. At the intersection of the canal with the marsh steam water works have been erected, with flood gates and dams by means of which the entire marsh may be flooded to a depth of a foot or more when desired. There are two engines of 150 horse power each, and two pumps that are capable of raising 80,000 gallons per minute.

When, in early autumn, the meteorological conditions indicate the approach of frost, the pumps may he put to work in the afternoon and the berries be effectually covered by water and thus protected before nightfall. At sunrise the gates are opened and the water allowed to run off again, so that the pickers may proceed with their work. The marsh is flooded to a depth of about two feet at the beginning of each winter and allowed to remain so until spring, the heavy body of ice that forms preventing the upheaval that would result from freezing and thawing—a natural process which, if permitted, works injury to the vines.

There is a three-story warehouse on the marsh, with a capacity of 20,000 barrels of berries, and four large two-story houses capable of furnishing shelter for 1,500 pickers. The superintendent's residence is a comfortable cottage house, surrounded by giant oaks and elms, and stands near the warehouse on an "island," or small tract of high, dry land near the center of the great marsh. The pickers' quarters stand on another island about 200 yards away.

A plank roadway, built on piles, about two feet above the level of the ground, leads from the mainland to the warehouse and other buildings, a distance of more than half a mile. Several wooden railways diverge from the warehouse to all parts of the marsh, and on them flat cars, propelled by hand, are sent out at intervals during the picking season to bring in the berries from the hands of the pickers. Each picker is provided with a crate, holding just a bushel, which is kept close at hand. The berries are first picked into tin pans and pails, and from these emptied into the crates, in which they are carried to the warehouse, where an empty crate is given the picker in exchange for a full one. Thus equipped and improved, the Sackett marsh is valued at $150,000. Thirteen thousand barrels have been harvested from this great farm in a single season. The selling price in the Chicago market varies, in different seasons, from $8 to $16 per barrel. There are several other marshes of various sizes in the vicinity.

The picking season usually begins about Sept. 1, and from that time until Oct. 1 the marshes swarm with men, women, and children, ranging in age from six to eight years, made up from almost every nationality under the sun. Bohemians and Poles furnish the majority of the working force, while Germans, Irish, Swedes, Norwegians, Danes, negroes, Indians, and Americans contribute to the motley contingent. They come from every direction and from various distances, some of them traveling a hundred miles or more to secure a few days' or weeks' work. Almost every farmer or woodsman living anywhere in the region of the marshes turns out with his entire family; and the families of all the laboring men and mechanics of the surrounding towns and cities join in the general hegira to the bogs, and help to harvest the fruit. Those living within a few miles go out in the morning and return home at night, taking their noon-day meal with them, while those from a distance take provisions and bedding with them and camp in the buildings provided for that purpose by the marsh owners, doing their own cooking on the stoves and with the fuel furnished them.

The wages vary from fifty cents to a dollar a bushel, owing to the abundance or scarcity of the fruit. A good picker will gather from three to four bushels a day where the yield is light, and five to six bushels where it is good. The most money is made by families numbering from half a dozen to a dozen members. Every chick and child in such families over six years old is required to turn out and help swell the revenue of the little household, and the frugal father often pockets ten to twenty dollars a day as the fruits of the combined labors. The pickers wade into the grass, weeds, and vines, however wet with dew or rain, or however deeply flooded underneath, making not the slightest effort to keep even their feet dry, and after an hour's work in the morning are almost as wet as if they had swum a river. Many of them wade in barefooted, others wearing low cowhide shoes, and their feet, at least, are necessarily wet all day long. In many cases their bodies are thinly clad, and they must inevitably suffer in frosty mornings and evenings and on the raw, cold, rainy days that are frequent in the autumn months in this latitude; yet they go about their work singing, shouting, and jabbering as merrily as a party of comfortably clad school children at play. How any of them avoid colds, rheumatism, and a dozen other diseases is a mystery; and yet it is rarely that one of them is ill from the effects of this exposure. As many as 3000 or 4000 pickers are sometimes employed on a single marsh when there is a heavy crop, and an army of such ragamuffins as get together for this purpose, scattered over a bog in confusion and disorder, presents a strange and picturesque appearance.

Indians are not usually as good pickers as white people, but in the sparsely settled districts, where many of the berry farms are situated, it is impossible to get white help enough to take care of the crop in the short time available for the work, and owners are compelled to employ the aborigines. A rake, with the prongs shaped like the letter V, is used for picking in some cases, but owing to the large amount of grass and weeds that grow among the vines on these wild marshes, this instrument is rarely available. After being picked the berries are stored in warehouses for a period varying from one to three weeks. They are washed and dried by being passed through a fanning mill made for the purpose, and are then allowed to cure and ripen thoroughly before they are shipped to market.

From statistics gathered by the American Cranberry Growers' Association it is learned that in 1883 Wisconsin produced 135,507 bushels, in 1884 24,738 bushels, in 1885 264,432 bushels, and in 1886 70,686 bushels of this fruit. By these figures it will be seen that the yield is very irregular. This is owing, principally, to the fact that many of the marshes are not yet provided with the means of flooding, and of course suffer from worms, droughts, late spring or early autumn frosts, and extensive fires started by sparks from the engines on railroads running through the marshes. These and various other evils are averted on the more improved farms. So that, while handsome fortunes have in many cases been made in cranberry growing, many thousands of dollars have, on the other hand, been sunk in the same industry. Only the wealthier owners, who have expended vast sums of money in improving and equipping their property, can calculate with any degree of certainty on a paying crop of fruit every year.

Chicago is the great distributing point for the berries produced in Wisconsin, shipments being made thence to nearly every State and Territory in the Union, to Canada, to Mexico, and to several European countries. Berries sent to the Southern markets are put up in watertight packages, and the casks are then filled with water, this being the only means by which they can be kept in hot weather. Even in this condition they can only be kept a few days after reaching hot climates.—American Magazine.

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SOUDAN COFFEE.

(Parkia biglobosa.)

There are valuable plants on every continent. Civilized Europe no longer counts them. Mysterious Africa is no less largely and spontaneously favored with them than young America and the ancient territory of Asia.

The latter has given us the majority of the best fruits of our gardens. We have already shown how useful the butter tree (Butyrospermum Parkii) is in tropical Africa, and we also know how the gourou (Sterculia acuminata) is cultivated in the same regions. But that is not all, for the great family of Leguminosae, whose numerous representatives encumber this continent, likewise furnishes the negro natives a food that is nearly as indispensable to them as the gourou or the products of the baobab—another valuable tree and certainly the most widely distributed one in torrid Africa. This leguminous tree, which is as yet but little known in the civilized world, has been named scientifically Parkia biglobosa by Bentham. The negroes give it various names, according to the tribe; among the Ouloffs, it is the houlle; among the Mandigues, naytay; in Cazamance (Nalon language), it is nayray; in Bornou, rounuo; in Haoussa, doroa; in Hant-fleure (Senegal), nayraytou. On the old mysterious continent it plays the same role that the algarobas do in young America. However, it is quite a common rule to find in the order Leguminosae, and especially in the section Mimosae, plants whose pods are edible. Examples of this fact are numerous. As regards the Mediterranean region, it suffices to cite the classic carob tree (Ceratonia siliqua), which also is of African nationality, but which is wanting in the warm region of this continent.

Throughout the tropical region of Africa, the aborigines love to consume the saccharine pulp and the seed contained in the pod of the houlle. Prepared in different ways, according to tribe and latitude, these two products constitute a valuable aliment. The pulp is consumed either just as it is or as a fermented beverage. As for the seeds, they serve, raw or roasted, for the production of a tea-like infusion (whence the name "Soudan coffee"), or, after fermentation in water, for making a national condiment, which in certain places is called kinda, and which is mixed with boiled rice or prepared meats. This preparation has in most cases a pasty form or the consistency of cohesive flour; but in order to render its carriage easier in certain of the African centers where the trade in it is brisk, it is compressed into tablets similar to those of our chocolate. As these two products are very little known in Europe, it has seemed to us that it would be of interest to give a description and chemical analysis of them. We shall say but little of the plant, which has sufficiently occupied botanists.



The houlle (Parkia biglobosa) is a large tree from 35 to 50 feet in height, with a gray bark, many branches, and large, elegant leaves. The latter are compound, bipinnate (Fig. 7), and have fifty pairs of leaflets, which are linear and obtuse and of a grayish green. The inflorescence is very pleasing to the eye. The flowers, say the authors of the Florae Senegambiae Tentamen, form balls of a dazzling red, contracted at the base, and resembling the pompons of our grenadiers (Fig. 8). The support of this latter consists only of male flowers. The fruit that succeeds these flowers is supported by a club-shaped receptacle. It consists of a large pod, which at maturity is 13 inches in length by 10 in width (Fig. 1). This pod is chocolate brown, quite smooth or slightly tubercular, and is swollen at the points where the seeds are situated. The pods are straight or slightly curved. The aborigines of Rio Nunez use the pods for poisoning the fishes that abound in the watercourses. We do not know what the nature of the toxic principle is that is contained in these hard pods, but we well know the nature of the yellowish pulp and of the seeds that entirely fill the pods.



Although the pulp forms a continuous whole, each seed easily separates from the following and carries with it a part of the pulp that surrounds it and that constitutes an independent mass (Fig. 2). This pulpy substance, formed entirely of oval cells filled with aleurone, consists of two distinct layers. The first, an external one of a beautiful yellow, is from 10 to 15 times bulkier than the internal one, which likewise is of a beautiful yellow.



It detaches itself easily from the seed, while the internal layer, which adheres firmly to the exterior of the seed, can be detached only by maceration in water. This fresh pulp has a sweet and agreeable although slightly insipid taste. Upon growing old and becoming dry, it takes on a still more agreeable taste, for it preserves its sweetness and gets a perfume like that of the violet.

As for the seed, which is of a brown color and provided with a hard, shining skin, that is 0.4 inch long, 0.3 inch wide, and 0.2 inch thick. It is oval in form, with quite a prominent beak at the hilum (Fig. 4). The margin is blunt and the two convex sides are provided in the center with a gibbosity limited by a line parallel with the margin, and this has given the plant its specific name of biglobosa. The mean weight of each seed is 41/2 grains. The skin, though thick, is not very strong. It consists, anatomically, of four layers (Fig. 5) of a thick cuticle, c; of a zone of palissade cells, z p; of a zone of cells with thick tangential walls arranged in a single row; and of a zone tougher than the others, formed of numerous cells with thick walls, without definite form, and filled with a blackish red coloring matter, cs. This perisperm covers an exalbuminous embryo formed almost entirely of two thick, greenish yellow cotyledons having a strong taste of legumine.

When examined under the microscope, these cotyledons, the alimentary part of the seed, have the appearance represented in Fig. 6, where ep is the epidermic layer and cp constitutes the uniform parenchyma of the cotyledonary leaf. This parenchymatous mass consists of oval cells filled with fatty matter and granules of aleurone.

According to some chemical researches made by Professor Schlagdenhauffen, the pulp has the following composition per 100 parts:

Fatty matter 2.407 Glucose 33.92 Inverted sugar 7.825 Coloring matter and free acids 1.300 Albuminous matter 5.240 Gummy matter 19.109 Cellulose 8.921 Lignose 17.195 Salts 4.080 ———- Total 100.000

The salient point of these analytical results is the enormous quantity of matter (nearly 60 per cent.) formed almost exclusively by sugar. It is not surprising, from this that this product constitutes a food both agreeable and useful.

An analysis of the entire seed, made by the same chemist, has given the following results:

Solid fatty matter 21.145 Unreduced sugar 6.183 Undetermined matters 5.510 Gummy " 10.272 Albuminoid " 24.626 Cellulosic " 5.752 Lignose and losses 20.978 Salts 5.534 ———- Total 100.000

The presence in these seeds of a large quantity of fatty matters and sugar, and especially of albuminoid matters (very nutritive), largely justifies the use made of them as a food. The innate instinct of the savage peoples of Africa has thus anticipated the data of science.—La Nature.

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THE HEIGHT OF SUMMER CLOUDS.

A knowledge of the heights and movements of the clouds is of much interest to science, and of especial importance in the prediction of weather. The subject has therefore received much attention during recent years from meteorologists, chiefly in this country and in Sweden. In the last published report of the Meteorological Council for 1885-86 will be found an account of the steps taken by that body to obtain cloud photographs; and in the Meteorologische Zeitschrift for March last, M.M. Ekholm and Hagstrom have published an interesting summary of the results of observations made at Upsala during the summers of 1884-85. They determined the parallax of the clouds by angular measurements made from two stations at the extremities of a base of convenient length and having telephonic connection. The instruments used were altazimuths, constructed under the direction of Prof. Mohn, specially for measuring the parallax of the aurora borealis. A full description of these instruments and of the calculations will be found in the Acta Reg Soc. Sc. Ups., 1884. The results now in question are based upon nearly 1,500 measurements of heights; the motions will form the subject of a future paper. It was found that clouds are formed at all levels, but that they occur most frequently at certain elevations or stages. The following are, approximately, the mean heights, in feet, of the principal forms: Stratus, 2,000; nimbus, 5,000; cumulus (base) 4,500, (summit) 6,000; cumulo-stratus (base), 4,600; "false-cirrus" (a form which often accompanies the cumulo-stratus), 12,800; cirro cumulus, 21,000; cirrus, 29,000 (the highest being 41,000). The maximum of cloud frequency was found to be at levels of 2,300 and 5,500 feet.

Generally speaking, all the forms of cloud have a tendency to rise during the course of the day; the change, excepting for the cumulus form, amounting to nearly 6,500 feet. In the morning, when the cirrus clouds are at their lowest level, the frequency of their lowest forms—the cirro-cumulus—is greatest; and in the evening, when the height of the cirrus is greatest, the frequency of its highest forms—the cirro-stratus—is also greatest. With regard to the connection between the character of the weather and the height of the clouds, the heights of the bases of the cumulus are nearly constant in all conditions. The summits, however, are lowest in the vicinity of a barometric maximum. They increase in the region of a depression, and attain their greatest height in thunderstorms, the thickness of the cumulo stratus stretching sometimes for several miles. The highest forms of clouds appear to float at their lowest levels in the region of a depression. The forms of clouds are identical in all parts of the world, as has been shown in papers lately read by the Hon. R. Abercromby before the English and Scottish Meteorological Societies.—Nature.

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ON THE CAUSE OF IRIDESCENCE IN CLOUDS.

By G. JOHNSTONE STONEY.

When the sky is occupied by light cirro-cumulus cloud, an optical phenomenon of the most delicate beauty sometimes presents itself, in which the borders of the clouds and their lighter portions are suffused with soft shades of color like those of mother-of-pearl, among which lovely pinks and greens are the most conspicuous. Usually these colors are distributed in irregular patches, just as in mother-of-pearl; but occasionally they are seen to form round the denser patches of cloud a regular colored fringe, in which the several tints are arranged in stripes following the sinuosities of the outline of the cloud.

I cannot find in any of the books an explanation of this beautiful spectacle, all the more pleasing because it generally presents itself in delightful summer weather. It is not mentioned in the part of Moigno's great Repertoire d'Optique which treats of meteorological optics, nor in any other work which I have consulted. It seems desirable, therefore, to make an attempt to search out what appears to be its explanation.

At the elevation in our atmosphere at which these delicate clouds are formed the temperature is too low, even in midsummer, for water to exist in the liquid state; and accordingly, the attenuated vapor from which they were condensed passed at once into a solid form. They consist, in fact, of tiny crystals of ice, not of little drops of water. If the precipitation has been hasty, the crystals will, though all small, be of many sizes jumbled together, and in that case the beautiful optical phenomenon with which we are now dealing will not occur. But if the opposite conditions prevail (which they do on rare occasions), if the vapor had been evenly distributed, and if the precipitation took place slowly, then will the crystals in any one neighborhood be little ice crystals of nearly the same form and size, and from one neighborhood to another they will differ chiefly in number and size, owing to the process having gone on longer or taken place somewhat faster, or through a greater depth, in some neighborhoods than others. This will give rise to the patched appearance of the clouds which prevails when this phenomenon presents itself. It also causes the tiny crystals, of which the cloud consists, to grow larger in some places than others.

Captain Scoresby, in his "Account of the Arctic Regions," gives the best description of snow crystals formed at low temperatures with which I am acquainted. From his observations it appears—(a) that when formed at temperatures several degrees below the freezing point, the crystals, whether simple or compound, are nearly all of symmetrical forms; (b) that thin tabular crystals are extremely numerous, consisting either of simple transverse slices of the fundamental hexagon or, more frequently, of aggregations of these attached edgewise and lying in one plane; and (c) that, according as atmospheric conditions vary, one form of crystal or another largely preponderates. A fuller account of these most significant observations is given in the appendix to this paper.

Let us then consider the crystals in any one neighborhood in the sky, where the conditions that prevail are such as to produce lamellar crystals of nearly the same thickness. The tabular plates are subsiding through the atmosphere—in fact, falling toward the earth. And although their descent is very slow, owing to their minute size, the resistance of the air will act upon them as it does upon a falling feather. It will cause them, if disturbed, to oscillate before they settle into that horizontal position which flat plates finally assume when falling through quiescent air. We shall presently consider what the conditions must be, in order that the crystals may be liable to be now and then disturbed from the horizontal position. If this occasionally happens, the crystals will keep fluttering, and at any one moment some of them will be turned so as to reflect a ray from the sun to the eye of the observer from the flat surface of the crystal which is next him. Now, if the conditions are such as to produce crystals which are plates with parallel faces, and as they are also transparent, part only of the sun's ray that reaches the front face of the crystal will be reflected from it; the rest will enter the crystal, and, falling on the parallel surface behind, a portion will be there reflected, and passing out through the front face, will also reach the eye of the observer.

These two portions of the ray—that reflected from the front face and that reflected from the back—are precisely in the condition in which they can interfere with one another, so as to produce the splendid colors with which we are familiar in soap bubbles. If the crystals are of diverse thicknesses, the colors from the individual crystals will be different, and the mixture of them all will produce merely white light; but if all are nearly of the same thickness, they will transmit the same color toward the observer, who will accordingly see this color in the part of the cloud occupied by these crystals. The color will, of course, not be undiluted; for other crystals will send forward white light, and this, blended with the colored light, will produce delicate shades in cases where the corresponding colors of a soap bubble would be vivid.

We have now only to explain how it happens that on very rare occasions the colors, instead of lying in irregular patches, form definite fringes round the borders of the cloudlets. The circumstances that give rise to this special form of the phenomenon appear to be the following: While the cloud is in the process of growth (that is, so long as the precipitation of vapor into the crystalline state continues to take place), so long will the crystals keep augmenting. If, then, a cloudlet is in the process of formation, not only by the springing up of fresh crystals around, but also by the continued growth of the crystals within it, then will that patch of cloud consist of crystals which are largest in its central part, and gradually smaller as their situation approaches the outside. Here, then, are conditions which will produce one color round the margin of the cloud, and that color mixed with others, and so giving rise to other tints, farther in. In this way there comes into existence that iris-like border which is now and then seen.

The occasional upsetting of the crystals, which is required to keep them fluttering, may be produced in any of three ways. The cloudlets may have been formed from the blending together of two layers of air saturated at different temperatures, and moving with different velocities or in different directions. Where these currents intermix, a certain amount of disturbance will prevail, which, if sufficiently slight, would not much interfere with the regularity of the crystals, and might yet be sufficient to occasion little draughts, which would blow them about when formed. Or, if the cold layer is above, and if it is in a sufficient degree colder, there need not be any previous relative motion of the two layers; the inevitable convection currents will suffice. Another, and probably the most frequent, cause for little breezes in the neighborhood of the cloudlets is that when the cloudlets are formed they immediately absorb the heat of the sun in a way that the previously clear air had not done. If they absorb enough, they will rise like feeble balloons, and slight return currents will travel downward round their margins, throwing all crystals in that situation into disorder.

I do not include among the causes which may agitate the crystals another cause which must produce excessively slight currents of air, namely, that arising from the subsidence of the cloudlets owing to their weight. The crystals will fall faster wherein cloud masses than in the intervening portions where the cloud is thinner. But the subsidence itself is so slow that any relative motions to which differences in the rate of subsidence can give rise are probably too feeble to produce an appreciable effect. Of course, in general, more than one of the above causes will concur; and it is the resultant of the effects which they would have separately produced that will be felt by the crystals.

If the precipitation had taken place so very evenly over the sky that there were no cloudlets formed, but only one uniform veil of haze, then the currents which would flutter the crystals may be so entirely absent that the little plates of crystals can fixedly assume the horizontal position which is natural to them. In this event the cloud will exhibit no iridescence, but, instead of it, a vertical circle through the sun will present itself. This, on some rare occasions, is a feature of the phenomenon of parhelia.

It thus appears that the occasional iridescence of cirrus clouds is satisfactorily accounted for by the concurrence of conditions, each of which is known to have a real existence in nature....—Phil. Mag., July 1887.

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