first in the group of five academies, by which, under the name of the Institut, the people of France provide for the preservation and improvement of their language, for the promotion of history, for the advancement of science, for the encouragement of art, and for the establishment of just ideas in morals and politics.

THE SOCIETY FOR THE PROMOTION OF AGRICULTURAL SCIENCE.

THE sixth annual meeting of this society at Ann Arbor, Aug. 25, may fairly be said to have been the best of the number, whether as regards the attendance of members and others, the number and character of the papers read, or the general interest and profit of the discussions.

The meeting was opened on Tuesday morning by a paper from Mr. J. J. Thomas of New York, upon 'The influence of locality upon varieties of fruit,' in which the author opposed the opinion which has been advanced by eminent pomologists, that varieties of fruit raised on our own soil and in our own localities are, on that account, better suited to this country. As regards pears, fully half our varieties are of foreign origin; and very many of these are among our most esteemed varieties, notably the Bartlett, and can hardly be equalled by the same number of native varieties. In the case of the apple, while many good varieties are of foreign origin, this fruit has been so extensively and successfully cultivated in America that our best varieties have come to be those of native origin. At the same time, most of the esteemed western and southern varieties are of eastern origin. The apple is very susceptible to influences of locality during the growth and ripening of the fruit; and this fact, rather than any differences due to origin, accounts for the preference shown for different varieties in different regions.

In the discussion following the paper, attention was called by Dr. E. L. Sturtevant to what appears to be the fact, that well-ripened specimens of any fruit are of the highest flavor in the most northern localities, while the size and appearance usually improve as one goes southward; and he suggested as a possible explanation the influence of actinism. During the growing season, plants receive more hours of sunlight in northern than in southern localities; and it is possible that this has something to do with their higher flavor. The subject is an important one for investigation. He also described a simple and inexpensive apparatus for automatically recording the number of hours of sunlight daily, without reference to intensity. This apparatus is now in use at the N. Y. experiment station; and the U. S. signal service is considering its introduction at a number of stations, in the hope that a record of the hours of sunlight may at least show whether it is desirable to attack the much more difficult problem of measuring its actinic intensity.

Prof. W. J. Beal confirmed Dr. Sturtevant's state

ment as to the flavor of fruit from northern and southern localities as regards Michigan fruits. Mr. Crozier instanced an experiment in which flowers from the same seed grown in Paris and in Upsala were much brighter colored in the more northern locality. Prof. I. P. Roberts called attention to the fact, that the soil has also much to do with the flavor of apples, stating that about Ithaca, N.Y., the best apples were grown on a clay soil and in elevated localities.

Following Mr. Thomas's paper were two by Dr. E. L. Sturtevant of New York, upon the 'dandelion' and 'lettuce.' These papers were in support of the hypothesis that the form-species of cultivated plants are not originated by culture, but are really selections from wild types. Thus in Vilmorin, Andrieux et Cie's seed-catalogue, three distinct varieties of dandelion are figured. Upon the grounds of the N. Y. experiment station, there are to be found growing wild, under conditions which seemingly preclude the possibility of their being escapes from cultivation, dandelions corresponding very closely to these three varieties. Moreover, two of these three varieties are figured respectively by Anton Pinaeus in 1561, and by Dodonaeus in 1616.

If it be granted, upon this evidence, that the cultivated varieties of dandelion are simply selections from wild types, "it may be legitimately questioned whether other of our cultivated form-species in other plants are not likewise of natural origin. A careful investigation into the history of the origin of our cultivated varieties, fully justifies the statement that I have as yet secured no data which justify the belief that form-species in culture are other than of natural origin; and I have secured much evidence in favor of the view that form-species are introductions from natural variations."

The paper upon lettuce is in further confirmation of this hypothesis. It should be said, however, that the author expressly recognizes the fact that much further study is necessary before so radical a belief can receive countenance.

In the ensuing discussion, Professor Bailey called attention to the fact that variable wild plants are those most likely to be selected for improvement, as to a certain extent sustaining the hypothesis advanced in the papers.

The afternoon session was opened by a paper upon 'The demands made by agriculture upon the science of botany,' by Prof. C. E. Bessey of Nebraska. The paper was devoted to the subject of the teaching of botany in colleges; and the writer made an earnest plea for the more extensive and thorough study of this science, classifying the demands made upon it by agriculture under three heads: First, a nomenclature and classification of the plants of the farm, cultivated as well as wild. Second, a better knowledge of the physiology of plants, including such subjects as growth and nutrition, fertilization, heredity, and the physiology of cultivation and improvement. Third, a better knowledge of the pathology of plants, particularly of that ill-defined state known as 'lowered vitality.'

Several speakers following Professor Bessey, commended the sentiments of his paper, and deprecated the undue attention given to systematic botany in many cases, where the chief end of the study seems to be to enable the student to find out the technical name of the plant.

A paper by Prof. T. J. Burrill of Illinois, upon 'An experiment in silk-culture,' came next upon the programme. The experiment was but very partially successful as regards the production of silk, the larger part of the worms dying of a contagious disease at about the time when they should have formed cocoons. The investigation of this disease formed the main subject of the paper. The disease was identified by the author, and by Professor Forbes, with the flacherie of Pasteur, and was plainly not the disease which he describes under the name pébrine. It also appears to be identical with a disease which has lately proved very fatal to the larvae of the cabbage butterfly.

The writer was not aware that any one had previously positively determined the existence of true flacherie, or of pébrine in America; but, if the conclusions of his paper were correct, the former, at least, has, in all probability, long existed here unrecognized.

In remarking upon the above papers, Prof. C. V. Riley claimed that both these diseases of the silkworm had been recognized by entomologists in this country, though they had not been able to give the disease that careful microscopical and bacteriological study which Professors Burrill and Forbes had done. He also stated his belief that the germs of flacherie are omnipresent, and that the disease may be induced at any time by unsanitary conditions.

A paper followed by Major Henry E. Alvord of New York, upon Telemetric aid to meteorological records,' describing briefly an apparatus made by the Telethermometer company of New-York city, by which a continuous record of temperature can be obtained at any reasonable distance from the place of observation, and with very little trouble. The results of about six months' comparison of one of these instruments, with thirteen daily readings of a standard mercurial thermometer, showed a tolerably close agreement between the two. The telethermometer was slightly tardy in its changes, and usually failed markedly to reach the minimum daily temperature, and frequently fell a little short of the maximum. The author considered it-though by no means perfect to be the best aid yet found for recording atmospheric temperatures in connection with agricultural studies.

The next paper was by Prof. H. P. Armsby of Wisconsin, upon The creaming of milk by the Cooley system.' It was chiefly statistical, giving the results of some two hundred and fifty experiments in creaming the milk of single cans by this system; and showing that in eleven hours 90-99 per cent of the fat of the milk was recovered in the cream, as against 75-80 per cent in some recently reported German experiments in which the temperature of the water surrounding the cans of milk was much higher. The experiments furnished also some hints as to further investigations upon the

influence of small variations of temperature upon the process, but no definite conclusions.

A paper by Prof. G. C. Caldwell of New York, upon "The lactobutyrometer,' consisted chiefly of a review of the tests of this instrument on record; but contained also some experiments as to the cause of the failure of the process in certain cases to extract even approximately all the fat from milk, particularly that from highly-fed cows. The author concludes that his experiments are at least not inconsistent with the belief that either an albuminous envelope, or some sort of an accumulation of albuminoid matter about the fat globules, gives rise to the difficulty.

A brief report by Prof. W. J. Beal, upon the progress of experiments on the vitality of buried seeds, and a short account by Prof. C. V. Riley of a new remedy for locusts, which has been successfully used in California, and the reading by title of a paper by Prof. E. W. Hilgard "On some redeeming traits of 'alkali' soils," closed the reading of papers.

At the business meeting, the following officers were elected for the ensuing year: President, Henry E. Alvord; secretary and treasurer, B. D. Halsted; executive committee, Henry E. Alvord, B. D. Halsted, and E. M. Shelton.

THE DEVELOPMENT OF THE EYE.

IN a recent paper before the Philadelphia academy, Dr. Benjamin Sharp has endeavored to trace the development of the highly complex vertebrate eye from the simplest deposit of pigment in an epithelial cell. The simplest organ of vision is found in the Lamellibranchiata; but these are not the primitive organs of the group, the ancestral eyes being present in a few forms for a short time during the free larval stage. The most primitive adult eyes are found in the common oyster, in which the free edge of the

FIG. 1. Visual cells of Ostrea virginica. c, cuticle; p, pig. ment; n, nucleus.

mantle is lined with a number of epithelial cells (fig. 1) having a nucleus (n), a deposit of pigment (p), a transparent cuticula (c), with an undoubted power of vision. The next step of advance is illustrated in the common Venus, in which the eyes

are confined to the most exposed part of the body, the so-called siphon. So far there has been no protection to the visual organs other than that afforded by the shell; but in Venus the fact that there are pigment cells at the base as well as on the extremities of the tentacles indicates a change soon o take place. This change is well shown in the razor-shell Solen (fig. 2), where all the eyes are arranged about the base of the tentacles, and, furthermore, are sunk into deep grooves. The organ is also much more perfect.

FIG. 2.- One visual cell of Solen vagina. c, cuticle; P, pigment; n, nucleus.

In the Gastropoda, from which the lamellibranchs have probably degenerated, the visual organs take

their morphological position at the oral end of the body; and, with only one or two exceptions, there is but a single pair of eyes. In Patella, the row of eyes last seen in Solen has become a simple sphere of pigmented cells; and in Haliotis we have also an open sphere, but, instead of the refractive cuticula in front of each cell, there is one combined mass forming a lens, which is purely a secretion, not cellular as in vertebrates. Fissurella goes practically as far as any gastropod, having a closed eye containing a lens, and a transparent epidermal covering acting as a cornea. Both Fissurella and Haliotis have a distinct nerve specialized for sight, which connects the eye with the superior cephalic ganglion.

In an early stage of the vertebrate embryo, the anterior medullary groove divides into three segments, the fore, mid, and hind brain. The fore-brain sends outwards and laterally a swelling, which increases in size, and passes on to the epidermis; and here an invagination takes place to meet this outward braingrowth. This invagination finally closes, and soon becomes cut off, forming a hollow vesicle, the cavity of which is finally obliterated, and, becoming transparent, forms the lens of

a

FIG. 3.

the adult eye. In the mean time the growth from the brain has arched over and above this vesicle; and then, folding over laterally, it encloses the lens (fig. 3), which fills up the anterior opening of the cavity of this 'secondary optic vesicle.' After the closure is completed by the union of a and b, there is a double-walled vesicle, the interior wall giving rise to the many layered retina, while the external wall forms the pigment layer of the choroidea.

Diagram to illustrate the method by which the secondary optic vesicle encloses the lens which should fill up the open end. Eye of vertebrate.

The evolution of this eye seems simple; for, as soon as it became of importance to its possessor, a corresponding stimulation took place in the brain, where sight is without doubt seated. An increase of development began all along the tract, from the lens to the brain; and, as this increased, that part of the brain nearest the eye enlarged, and proceeded by steps outward in a manner similar to the process now taking place in the development of the eyes of Vertebrata. We then have a stage in which a part of the brain closes over the superior part of the eye, being separated by a layer of fibres which is the much shortened and flattened primitive optic nerve. The pedicle connecting this advanced part of the brain, which may be looked upon as a ganglion, will now be called the 'secondary optic nerve,' — the optic nerve of the eyes of the adult Vertebrata. Dr. Sharp thus holds, 1o, that the lens of the vertebrate eye is homologous with a primitive invaginated eye, such as we find to-day in the gasteropods; 2°, that the layer of optic fibres of the retina is homologous with the primitive optic nerve.

In vertebrates as well as invertebrates we frequently

find blind animals, the near relatives of which have well-developed organs of sight. In these cases the accessory organs are first to disappear, the lens first; and in the lowest forms of degeneration, Branchiostoma notably, nothing remains but a slight deposit of pigment on the anterior end of the neural canal. This deposit in Branchiostoma, and a similar deposit in some larval Ascidia, have led Lankester to regard the primitive type of Vertebrata as a transparent animal with eyes sessile in the brain; but Dr. Sharp's investigations have led him to the opinion that forms so degenerate as these should not be taken as a standard on which to base our conclusions in regard to the origin of the vertebrates.

CIVILIZATION AND EYESIGHT.

THE discussion following Lord Rayleigh's article upon Civilization and eyesight' (Nature, No. 798, p. 340) has resulted in a clear exposition of this interesting subject. Rayleigh is of the opinion that the supposed superiority of the savage eye is merely a question of attention, and practice in the interpretation of minute indications; and that it is comparable with the acuteness of the blind in drawing conclusions from slender acoustical premises. It is doubtful whether the blind can hear sounds wholly inaudible to others; and, likewise, it seems impossible for the savage eye, with practically the same aperture as the civilized eye, to resolve objects, beyond a certain point, calculable by the laws of optics from the wave-length of light.

J. Rand Capron (Nature, No. 799, p. 359) suggests that, in considering the question of aperture, the fact that this, though probably following a general rule applicable alike to savages and civilized beings, varies in individual cases, should be taken into account. He mentions an assistant who had a singularly 'sharp' eye, and could pick out with ease companions to double stars, small satellites, etc., which others saw with difficulty. The pupils of his eyes were always larger than those of most other persons; and he had the peculiar power of being able to read fine print with ease when the gas was turned half on, and it was his habitual custom to read in this way. He suggests that there must be something more than a mere 'question of attention and interpretation of minute details,' when a savage can resolve two distant dots into distinctly appreciable personages, as regards sex and garments.

R. Brudenell Carter urges (Nature, No. 800, p. 386) that there is no necessity for a larger aperture to explain acuteness of vision. The savage might have greater sensitiveness to variations of light, greater sensitiveness to color, and acuteness of vision over a larger retinal area. All these advantages might be conferred by better formation or higher development of the retina; and such higher development might at once be promoted by exercise, and handed down by descent. He believes that the conditions of town-life are unfavorable to the evolution, and favorable to the degradation, of the eye; and, further, that a mod

erate amount of attention might greatly modify these conditions, and might do for the eyes what is done by athletic games and exercises for the muscles.

A still different explanation of the phenomenon is given by G. B. Buckton (Nature, No. 801, p. 407). The same amount of light entering the eyes of different individuals produces widely different effects, according to health or age. A student becoming accustomed to see objects from a short distance, will permanently accommodate himself to a short focus, and hence become short-sighted. Such modifications can be conceived of as being hereditary, and longsight might be brought about in a race by the opposite use of the eye.

Apropos to this discussion, it may be well to notice briefly a discussion upon near-sightedness, which was started by Lord Rayleigh's article. The investigation of the question of the increasing prevalence of shortsight, which has recently been carried on in Germany, has led to legislative restrictions in the schools. The numerous statistics from the German schools have shown that the proportion of short-sighted boys continually increases from form to form; and from this fact it has been argued that the continued use of the eyes for the perception of near objects, is the essential, if not the only, factor in the production of shortsight. This view is again supported by the statistics, which allot the largest proportion of short-sighted individuals to those branches of industry, or those pursuits, which constantly call for near vision. In this connection, Mr. George A. Berry (Nature, No. 800, p. 387) suggests that two points have been forgotten in arriving at such a conclusion. In the first place, there is an undoubted tendency to grow shortsighted with age alone, up to the period of cessation of growth. This has been shown to be due to the elongation of the antero-posterior axis of the eye, and is no more a disease than is the attainment of more than an average height by certain individuals. It is merely a type; and, as such, is governed by the laws of heredity. A small proportion of cases are, however, due to disease; and these are as frequent among the illiterate as the educated, and are not hereditary. In many cases, people drift into literary and similar pursuits because they are near-sighted, and not well adapted for other occupations. Further, as a man's circle of acquaintance is, for the most part, amongst individuals having similar interests in life, intermarriage in myoptic families must frequently occur, and would tend to perpetuate, and perhaps increase, the defect. In savages, on the other hand, where the great principle of survival of the fittest is not frustrated to the same extent as among civilized races, every thing would be against the perpetuation of a myoptic type.

CHEYNE'S OBSERVATIONS ON THE

CHOLERA MICROBE.

IN connection with the work of Van Ermengem upon the cholera bacillus (Science, No. 133), that of

Cheyne, recently published (British med. journ., April 25-May 23, 1885), deserves attention. This gives the results of his investigations at Paris during the epidemic of cholera, and afterwards at his own laboratory. In eight cases investigated, he found the curved bacilli in larger or smaller numbers: in a ninth case, supposed to be cholera, but turning out not to be, no curved bacilli were found. He failed to demonstrate these bacilli in the walls of the intestines in almost all cases; and, when he succeeded in finding them at all, they were very indistinct. He very justly observes, however, that Koch may succeed in such a demonstration where others fail; for Koch's technique is unquestionably superior to that of any other worker in this field.

Having sent his slides and cultures to Koch, and having the latter's assurance that they were pure, and made up of the curved bacillus of Asiatic cholera, Cheyne made various experiments with them in culture-media of different kinds and at different temperatures, the results of all of which were in conformity with what was already known. In particular, he found no difficulty in repeating Koch's observation, that drying rapidly destroys the vitality of these organisms: in three hours they are completely dead.'

His conclusions are, that the comma bacillus was present, and generally in large numbers, in all the cases of cholera which were examined; and that he has never met with the cholera bacillus except in cholera, and that the other curved bacilli described (Finkler and Prior's, Lewis's, and Dencke's or Flügge's), differ from it in important particulars.

Inoculation experiments were performed on seventeen guinea-pigs, with successful results in only two. Two other animals died, but were not examined, because destroyed. (We would suggest greater care of his inoculated animals, for these misfortunes seem to be but a repetition of those that happened in this observer's work on tuberculosis; see Practitioner, April, 1883.)

The last part of Mr. Cheyne's article is devoted to an able refutation of Klein's arguments against the specific nature of the comma bacillus. He shows the hasty work of this observer, which has led him to conclusions so entirely at variance with those of Koch and his supporters. He (Cheyne) thus summarizes his opinion of the work of the English cholera commission: "The two errors which, in my opinion, lie at the root of the work of the English cholera commission are, first, that, acting on the idea that Koch diagnosed the cholera bacilli by the microscope alone, they proceeded to investigate the matter by microscopic examination; and, secondly, that, seeing the stress which Dr. Koch laid on the cultivation appearances, they concluded that he meant to say that the organism was pathogenic, because it grows in a particular manner: and, therefore, they naturally proceeded to inquire whether the appearance of the cultivations, as compared with cultivations of other bacteria, could warrant this conclusion; and, of course, they found that it could not."

In the middle or latter part of June, I think it was, - in 1882, I was prospecting on the head-waters of the Tumiche Creek in the Gunnison valley, Col. About nine o'clock in the morning, I sat down in the shade of some willows that skirted a clear but shallow place in the creek. In a quiet part of the water, where their movements were readily discernible, were some fresh-hatched brook or mountain trout; and circling about over the water was a small swarm of mosquitoes. The trout were very young, still having the pellucid sack puffing out from the region of the gills, with the rest of their body almost transparent when they would swim into a portion of the water that was lighted up by direct sunshine. Every few minutes these baby trout-for what purpose I do not know, unless to get the benefit of more air - would come to the surface of the water, so that the top of their head was level with the surface of the water. When this was the case, a mosquito would alight, and immediately transfix the trout by inserting his proboscis, or bill, into the brain of the fish, which seemed incapable of escaping. The mosquito would hold his victim steady until he had extracted all the life juices; and when this was accomplished, and he flew away, the dead trout would turn over on his back, and float down the stream. I was so interested in this before unheard of destruction of fish, that I watched the depredations of these mosquitoes for more than half an hour; and in that time over twenty trout were sucked dry, and their lifeless shells sent floating away with the current. It was the only occasion that I was ever witness to the fact, and I have been unable by inquiry to ascertain if others have observed a similar destruction of fish. I am sure the fish were trout, as the locality was quite near snow line, and the water very cold, and no other fish were in the stream at that altitude. From this observation, I am satisfied that great numbers of trout, and perhaps infant fish of other varieties in clear waters, must come to their death in this way; and, if the fact has not been heretofore recorded, it is important to those interested in pisciculture.

LAST YEAR'S MEETING OF THE
AMERICAN ASSOCIATION.

THE proceedings of the American association for the advancement of science for 1884 were ready for publication only just prior to the date appointed for the meeting at Ann Arbor. They extend through 736 pages, to which there is an index covering sixteen pages. As usual, a large part of the papers are represented only by titles and abstracts,

some others have already been printed; so that the volume is chiefly to be valued for reference, rather than for the freshness of its contents. It appears to have been carefully edited by the secretary, and to contain in exact and convenient forms all the general information respecting officers, membership, committees, and official acts to which we have been so long accustomed. Of course we cannot allude specifically to the long array of scientific communications here presented; but we will venture to call the attention of the general reader to the various addresses which he will find in the volume, and which, taken collectively, afford a very good insight into the aspect of scientific studies in this country and at this time.

A re-examination of the opening address of Prof. C. A. Young of Princeton, on the Pending problems in astronomy,' has confirmed our first impressions of its value. Indeed, we do not hesitate to call it a model discourse for such an occasion. The president of the association selected a theme which he was fully qualified to discuss, one which enabled him to look forward as well as backward, one which was of equal interest to the astronomer and to the students of other sciences. The style in which he wrote was bright, and fitted to engage the attention of any well-educated person, while it remained free from all that was extraneous or sensational. No better introduction can be found to the present condition of astronomical science.

The addresses of the vice-presidents are also given. That of Professor Eddy is a complaint and an appeal, with respect to the neglect of mathematics by our countrymen, and recalls a like complaint which was made by Professor Newton when he was sectional vice-president a few years ago, and a well-known article by Professor Newcomb in the North-American review for 1874. It is difficult to account for the intellectual abstinence of Americans, to which these writers refer, from domains so inexhaustible as those of modern mathematics, except by remembering the eagerness of everybody in this land - scholars and teachers, as well as investors and merchants — for immediate results, for the concrete rather than the abstract. Professor John Trowbridge entitles his address What is electricity?' — a question which he knows, as well as anybody, is easier asked than answered. Nevertheless, around this inquiry he has grouped a large number of important and suggestive statements, which were particularly appropriate at a time when the national electrical congress was about to meet in the city of Franklin. In