TOADS ON THE SEASHORE.

DURING a vacation recently spent at Cape May, New Jersey, I was much interested in observing the habits of the toads on the seashore. Between the 'board-walk' and high-water mark is a narrow belt of uneven sand, dotted with tufts of beach-grass and raised here and there into miniature 'dunes.' Here the toads congregate in considerable numbers, and as evening draws on they may be seen hopping about in quest of food. As they were not to be seen during the heat of the day, I became interested to know where they concealed themselves. A short search revealed their whereabouts. Like so many of the small animals of the contiguous waters, they bury themselves in the sand for concealment. Upon looking attentively over the surfaces of the little dunes, one saw here and there a pair of bright eyes, not unlike the sand in color and as fixed as gems in a rock. It was only necessary to touch the sand in the immediate vicinity of the eyes, when a toad would hop out and tumble clumsily over the hummocks in endeavors to escape.

Whether the toads captured any prey while concealed in the sand I was unable to discover, but I should think it improbable, as their mouths were usually beneath the surface and there would be little chance for them to shoot out their tongues.

FREDERICK W. TRUE.

GENERAL.

PROFESSOR ARTHUR CAYLEY, the eminent mathematician, died at Cambridge, England, on January 26, at the age of seventy-four.

JOHN S. BURDON-SANDERSON, M. A., Fellow of Magdalen College, and Waynflete Professor of Physiology, has been appointed Regius Professor of Medicine, at Oxford, in place of Sir Henry W. Acland, Bart., Christ Church, resigned. Professor Burdon-SanProfessor Burdon-Sanderson continues to direct the lectures and

practical instructions in the Department of Physiology, with the assistance of Dr. Hal

dane and Mr. Pembrey.

APPLICATIONS for the table at the Biological Laboratory of Cold Spring Harbor, maintained by the American Association should be sent to Professor W. H. Conn, Wesleyan University, Middletown, Conn., or to Professor F. W. Hooper, Brooklyn Institute of Arts and Sciences, Brooklyn, N. Y.

The Johns Hopkins University Circular for January consists of scientific notes on work done at the University. It includes a reprint from the Journal of Geology of Professor Brooks' paper, On the Origin of the Oldest Fossils and the Discovery of the Bottom of the Ocean, and a reprint from Natural

Science of a review of Professor Brooks'

monograph, The Genus Salpa. It also contains notes in chemistry, astronomy and botany.

THE French Minister of Education, M. Leygues, has opened the new buildings for the scientific departments of the Sorbonne.

THE list of books for sale issued by Bernard Quaritch in January includes many valuable works in natural history, especially in botany and ornithology.

SOCIETIES AND ACADEMIES.

NEW YORK ACADEMY OF SCIENCES.

Biological Section: January 14, 1895. Notes on Neurological methods and exhibition of photo-micrographs.

A paper on The Use of Formalin in Golgi's method was read by Mr. O. S. Strong. The writer found that formalin (40% solution of formaldehyde) may be used (instead of osmic acid) mixed with potassium bichromate. Pieces of adult brain were placed in the following: Potassium bichromate (3%-5%) 100 volumes + formalin 23 to 5 vol. During several days or more the tis

sue is transferred to the silver nitrate solution (1%). Or the tissue after 1 to 2 days may be transferred from the above bichromate-formalin mixture to the following: Pot. bich. (5%) 2 vols. + formalin 1 vol. After 12 to 24 hours the tissue is put into silver solution. The advantages of this method are that it avoids the use of osmic acid and that the stage of hardening favorable for impregnation lasts longer than when the osmium-bichromate mixture is used and good results are consequently more certain. In other words, the formalin-bichromate does not overharden. In this respect it is also superior to the lithium bichromate method of the author (N. Y. Acad. of Sc. Pro. vol. XIII., 1894). For embryonic tissue the formalin method is probably not equal to the osmium-bichromate method, possibly because it does not harden sufficiently. For such tissue lithium bichromate (which hardens more rapidly than potassium bichromate) had better be mixed with the formalin instead of potassium bichromate. While good results are obtainable, especially with advanced embryonic tissue, with either of the above, yet the author believes that for such tissue the osmium-bichromate method is probably in certain respects somewhat superior.

A fuller account will be published later. Dr. Ira Van Gieson reported some preliminary observations on the action of formalin as a fixative and preservative of the central nervous system for the ordinary histological staining methods; solutions of formalin, four, six and ten per cent. were used, followed by 95 per cent. alcohol and celloidin embedding. Sections of the human cord, cerebellum and cortex prepared in this way gave very thorough fixation of the ganglion cell, neuroglia cells, and fine nerve fibres. Weigert's haematoxylin method can be applied to such sections, and gives very good results for the plexus of fine fibres in the cortical and spinal grey matter. The

myelin of the fine fibres is well preserved and gives the characteristic bluish black reaction with the Weigert haematoxylin stain, as in chrome hardened preparations. The background of the grey matter is especially clear and the fibres sharply delineated. The formalin hardened sections should be soaked in the neutral copper acetate solution, diluted one-half with water, for 2 hours, then thoroughly washed in water and immersed in the Weigert lithium-carbonate haematoxylin solution two to twelve hours. Weigert's borax-prussiate of potassium solution is used for differentiation. The differentiation takes place rapidly and must be watched carefully.

The formalin sections of the central nervous system may also be used for Rehm's modification of Nissl's method; but the staining of the chromatin and minute structure of the nucleus and cytoplasm is not quite so sharply outlined as with absolute alcohol fixation.

The duration of the hardening in formalin solutions has a very important and varying influence on the nerve fibers and ganglion cells with reference to the application of such methods as the Weigert and Nissl groups of stains. A further study to define the more exact limitations of formalin as a new histological preservative for the nervous system will be published later and the more exact periods of time in the hardening necessary for different stains detailed.

Mr. R. H. Cunningham, On the Sources of Illumination for Photo-Micrography, noted a practical mode of employing the arc light with satisfactory results.

Mr. C. F. Cox illustrated the Latest Theories of Diatom Structure, exhibiting lantern slides of Mr. T. F. Smith, of London.

Dr. Edward Leaming projected a series of his micro-photographs of bacteria, fertilization processes of sea-urchin, Toxopeneustes, and Golgi preparations.

BASHFORD DEAN, Recording Secy.

THE BIOLOGICAL SOCIETY OF WASHINGTON, JAN. 26.

Council meeting at 7:30 P. M.

A New Cotton Enemy, brought over from Mexico: MR. L. O. HOWARD.

Anatomy of a Leaf-gall of Pinus virginianus: MR. THEO. HOLM.

Abnormal Feet of Mammals: MR. F. A. LUCAS. The Mesozoic Flora of Portugal compared with that of the United States: PROF. LESTER F. WARD.

FREDERIC A. LUCAS, Secretary.

SCIENTIFIC JOURNALS.

THE ASTROPHYSICAL JOURNAL, JAN. On the Conditions which Affect the Spectro-Photography of the Sun: A. A. MICHELSON. Photographs of the Milky-Way: E. E. BAR

NARD.

The Arc-Spectra of the Elements I. Boron and Berylium: H. A. ROWLAND and R. TAT

NALL.

On Some Attempts to Photograph the Solar Corona Without an Eclipse, made at the Mount Etna Observatory: A. Riccò.

Discovery of Variable Stars from their Photo

graphic Spectra: E. C. PICKERING. Preliminary Table of Solar Spectrum Wave

Lengths I.: H. A. ROWLAND.

Observations of Mars made in May and June, 1894, with the Melbourne Great Telescope: R. L. J. ELLERY.

Recent Changes in the Spectrum of Nova Auriga W. W. CAMPBELL.

The Modern Spectroscope. X. General Considerations Respecting the Design of Astronomical Spectroscopes: F. L. O. WADSWORTH.

Minor Contributions and Notes.

Reviews.

Recent Publications.

AMERICAN JOURNAL OF MATHEMATICS, JAN.

On the First and Second Logarithmic Derivatives of Hyperelliptic Functions: By OSKAR BOLZA.

Sur la definition de la limite d'une fonction. Exercice de logique mathématique: Par G.

PEANO.

Theorems in the Calculus of Enlargement: By EMORY MCCLINTOCK.

On Foucault's Pendulum: By A. S. CHESSIN.

BULLETIN OF THE TORREY BOTANICAL CLUB, JAN.

Family Nomenclature: JOHN HENDLEY BARN

HART.

A Revision of the North American Species of the Genus Cracca: ANNA MURRAY VAIL. A Revision of the Genus Scouleria with Description of one new Species: ELIZABETH G. BRITTON.

Studies in the Botany of the Southeastern United States-III.: JOHN K. SMALL.

New Plants from Idaho: LOUIS F. HENDER

SON.

Buxbaumia Aphylla: GEO. G. KENNEDY. Herbert A. Young: WM. P. RICH.

Proceedings of the Club.

Index to Recent Literatare Relating to American Botany.

NEW BOOKS.

The Factors in Organic Evolution: A Syllabus of a Course of Elementary Lectures. DAVID STARR JORDON. Pp. 149. Ginn & Co. $1.50.

The Geological and Natural History Survey of Minnesota. N. H. WINCHELL. Minneapolis, Harrison & Smith. 1894. Pp. 210. Anatomy and Art. President's address before the Philosophical Society of Washington. ROBERT FLETCHER WASHINGTON. 1895. Pp. 24.

PAUL APPELL.

Extrait d'une lettre adressée à M. Craig: Par M. HERMITE.

the Smithsonian Institution, 1890-1891. J. W. POWELL. Washington, Government Printing Office. Pp. 742.

Photobacteriographs were made by Buchner's method, namely, by placing a square of black paper, or of glass of different colors, upon the bottom of a plate containing inoculated agar-agar during insolation; but although the protected portion was visible after fifteen minutes' insolation and incubation for twenty-four hours, and sharply defined after two hours' insolation and incubation as before, no accurate estimate could be made of the difference in the destructive power of different periods of insolation. Successful photobacteriography requires inoculation of large quantities of bacteria, in order that the colonies may be set so closely together that a ground-glass appearance is produced; in which case counting of the colonies is practically impossible.

For this reason the following method was used for each of the three organisms, the staphylococcus pyogenes aureus, the bacillus coli cammunis and the bacillus typhi abdominalis.

To obtain an accurate measure of the effects produced by lights of different intensity or of different colors, it is necessary to ensure, as far as possible, that the bacteria to be experimented on shall be uniformly distributed in the culture media. Tubes containing each 10 cc. of bouillon were inoculated with one drop of a bouillon culture and then placed in an incubator for twenty-four hours. A small quantity of sterilized gravel was then added to the culture tube and it was thoroughly shaken, after which 10 cc. of a one-half per cent. salt solution was added and the culture drawn into a Nuttall's dropping apparatus. From this, one-twentieth of 1 cc. of the bouillon culture was dropped into a tube of melted agar-agar, which was slowly and thoroughly agitated, and the contents were then poured into a Petri dish, carefully levelled on a levelling tripod over ice water. In the first method used the Petri dishes

were found to be so uneven on the bottom that the layer of medium under the protective square was often very thick or very thin as compared with that about the circumference of the plate, and, therefore, comparisons made between the centre and the circumference would be in almost every case unreliable. To overcome this difficulty, just one-half of the plate was shaded with black paper or colored glass.

The plates were then exposed to sunlight, bottom upwards, so as to allow the sun to shine as directly as possible on the inoculated agar-agar. At intervals of fifteen minutes a plate was removed and placed in the incubator. The temperature of the plates during insolation was always below 34° C. as shown by a thermometer with a blackened bulb which was placed in the sun and the temperature noted every fifteen minutes. Sunny, still days were utilized for insolation, beginning at 10 A. M. during the months of October, November and December. After insolation, the plates, and also a non-insolated control plate were incubated for twenty-four hours.

The colonies were counted in the following manner: A number 1 eye-piece was divided into fields (as done by Nuttall in counting tubercle bacilli), by introducing a disk of black cardboard which had a square opening divided into four parts by two hairs placed at right angles. This eye-piece and an objective of low power were used in counting. The percentage of germs destroyed by insolation was estimated from the mean of four counts taken on both the insolated and the protected halves of the plate. By this method an accurate statement can be made regarding the difference in protective power given by the different colors, not from simple observation, but by comparison of a definite number of colonies counted.

The following table shows the comparative effect of the blue rays and of complete