ated thirty yards from the nest, we found five. Of seventeen which had been retained seventy-two hours and were liberated thirty-five yards from the nest, we found eleven. Of thirteen which had been retained ninety-six hours and were liberated thirty-five yards from the nest, we found six. Of eight which had been retained forty-nine hours and were liberated two hundred and sixteen yards from the nest, we found none. It thus appears that wasps remember the locality of their nests for ninety-six hours.

We had hoped to collect a much larger store of facts upon this subject, but were prevented from doing so by the difficulty of keeping the wasps alive after we had taken them from the nest, and by a lack of material to work upon. We were able to find only one wasp-nest during the entire summer, although in the summer of the year before we had found thirty-three nests in the same neighborhood.

Our strictures upon the observations of others may seem hypercritical, but when it is remembered that the only warrant for making any inference whatever is based upon the supposition that a similarity in the actions of insects to those of man, under a given set of circumstances, is the result of a similarity in their mental processes, it will seem scarcely possible to be too guarded in drawing conclusions.-G. W. and E. G. Peckham.

MICROSCOPY.

Microtechnical Notes by Dr. Paul Mayer.-After describing the new water-bath and its accessories, Dr. Mayer proceeds to give the latest improvements in the methods employed at the Naples Zoological Station:

I. The Section-Smoother, or Planisher.2-The rod of the schnittstrecker, or planisher, as I shall call it, is not large enough to prevent very large sections from rolling a little. The defect is easily remedied by following the example of Vosmaer, who cuts off strips of the gelatin plates used by lithographers for tracing, and fastens them to the under side of the rod with very soft paraffine. In this manner the rod can readily be enlarged to any desired extent; and the transparency of the gelatin makes it possible to follow the sections as they pass under the rod.

2. Section-Fixatives.-Of the three fixatives now in general use, shellac, collodion, and albumen,-shellac is considered the

26.

Edited by C. O. WHITMAN, Ph.D., Milwaukee, Wisconsin.

Schnittstrecker" has been variously translated "section-smoother," "sectionstretcher," "section-flattener," etc. Perhaps the German name has been poorly chosen; at all events, our renderings of it are decidedly unsatisfactory names. The instrument is designed to prevent sections from curling; in other words, to keep them plane, or flat. The word planisher, taken in a strictly etymological sense, expresses the idea precisely enough, is both simple and intelligible. I venture, therefore, to propose it as a substitute for the awkward and clumsy compounds hitherto employed.

best for objects colored in toto. The carbolic-acid shellac introduced by Mayer has been found to be unreliable in some respects. Carbolic acid warm is injurious to some tissues,—e.g., the dermis of vertebrates. The alcoholic solution is a perfectly harmless fixative. The method of using, which differs in important points from the one prescribed by Giesbrecht, is as follows:

a. The object-slide, heated to about 50° C., is coated with shellac in the usual manner, by drawing a glass rod wet with the solution once or twice over its surface. As soon as the slide is cool and the film of shellac hard and no longer sticky, the sections are arranged dry, and then gently pressed down by means of an elastic spatula (horn or metal) until they lie flat and smooth on the slide.

b. Expose the slide thus prepared to the vapor of ether. For this purpose the slide may be placed in a glass cylinder of suitable size, and closely stoppered. The cylinder is placed in a horizontal position, or, at least, so inclined that the slide lies wholly above the ether. The saturation of the sections will be sufficiently complete in about half a minute.

c. The slide is next to be warmed in the water-bath in order to evaporate the ether. The paraffine is then removed and the mounting completed in the usual manner.

It is best to use balsam dissolved in turpentine or benzole rather than in chloroform, as the latter softens the shellac, and thus often loosens the sections.

One great advantage of this method of using shellac is that it permits of arranging and flattening the sections on the slide. Ordinarily sections are placed while the adhesive coating is soft, and must then lie as they fall.

With reference to collodion, Mayer remarks that it depends entirely upon the quality of the gun-cotton employed whether the sections bear well treatment with alcohol and aqueous fluids. When sections are to be stained on the slide, the albumen-fixative is preferred to collodion. This mixture is prepared as follows:

shaken together, Mayer has kept Other antiseptics

These ingredients are mixed and thoroughly then filtered and kept in a well-cleaned bottle. this mixture three years in a good condition. have proved far less efficient than salicylate of sodium.

3. Sublimate.-For the extraction of sublimate from tissues Mayer employs tincture of iodine. The tincture is added in small quantities to the alcohol in which the objects are preserved, as often as the color fades.

I

4. Mayer's Carmine.-This staining-fluid, previously described as "Alcohol Carmine," is a modification of Grenacher's acid carmine.

Carmine........

Water..........

Hydrochloric acid..

Alcohol (85%)....

Ammonia (enough to neutralize).

4 grm. 15 c.cm. 30 drops.

95 c.cm.

The pulverized carmine is mixed with the water and the acid, and dissolved by boiling. The alcohol is then added, and the solution neutralized by stirring in ammonia until a precipitate begins to appear. This method of procedure is safer than the one hitherto followed, according to which the carmine was dissolved by boiling in the alcohol plus the acid.

5. The Latest Camera Lucida of Abbe.-Zeiss makes two forms of the new Abbe camera lucida. Both are constructed on the same principle, but one (No. 70) has a larger mirror and a longer arm than the other (No. 69). The larger form-the one recommended by Dr. Mayer-is only made to order. The advantage of this form is that it enables one to utilize the whole field of vision without any perceptible distortion of the image, and is thus especially useful in drawing comparatively large objects with low powers. With the smaller camera (No. 69) the whole field can be projected on the drawing-paper only by giving the mirror an inclination differing so much from the angle (45°) required for accurate drawing that the image is more or less disproportioned.

The Abbe camera is superior to that of Oberhäuser in two important particulars: it gives a much larger field of vision and better light. Its construction does not admit of use with the microscope-tube in a horizontal pos: This is a defect which ought to be at once corrected.

The Abbe cameras, especially the larger one, can be used to great advantage with the embryograph of His. It is only necessary to add to the stand a horizontal arm, to which the camera can be fastened.

The construction of the Abbe camera is illustrated in the accompanying cut.

The drawing-surface is made visible by a double reflection from a large plane mirror, and from the silvered surface of a small prism in the visual point of the eye-piece. The microscopic image is seen directly through an apparatus in the silvering of the prism. By the concentricity thus obtained of the bundle of rays reaching the eye from both the microscope and the paper, the image and pencil are seen coincidently without any straining of the eyes. With this apparatus, moreover, drawWhitman, Methods of Research, etc., p. 39. 2 Zeiss's Catalogue, 1885, p. 44, No. 70.

ings may be executed on a horizontal surface without perceptible distortion. The brightness of the paper is regulated by smoke

tinted glasses which fit into the prism mounting. The apparatus is specially adjusted for the No. 2 Huyghenian eye-piece; mounted on this and fixed by a clamping screw the mirror only requires turning in the proper position and it is then ready for

use.

SCIENTIFIC NEWS.

The Proposed Monument to Audubon.-At the recent meeting in New York of the American Association for the Advancement of Science, the fact that the remains of the great naturalist, Audubon, lie in an obscure and little-visited portion of Trinity Cemetery, New York City, and that his tomb is unmarked by any distinguishing monument, was brought to the attention of the members. The demands upon the time of all in attendance at that meeting were so great that no action was taken by the Association, although the most lively interest was expressed by individual members, and the propriety of marking the restingplace of the founder of American Ornithology by a suitable monument was appreciated.

The Audubon plot in Trinity Cemetery will probably be disturbed by the continuation westward of One Hundred and Fiftythird Street. The trustees of the cemetery have, with commendable liberality, assigned the Audubon family a new lot close to One Hundred and Fifty-fifth Street, in full sight of Audubon Park and near the end of Audubon Avenue, when this shall be continued from the north, and are in hearty co-operation with the monument enterprise.

At the first autumn meeting of the New York Academy of Sciences a committee was appointed to solicit funds and make all arrangements for a monument.

Vice-President Trowbridge then appointed as such committee Prof. Thomas Egleston, of the School of Mines, Chairman, Prof. Daniel S. Martin, of Rutgers Female College, and Dr. N. L. Britton, of Columbia College. This committee has organ

ized with Dr. Britton as secretary and treasurer, and is now ready to receive subscriptions, which will be properly acknowledged. Checks should be made payable to N. L. Britton, Treasurer, and post-office orders should be drawn on Station H, New York City.

The committee estimates that between six and ten thousand dollars will be required to erect and engrave a shaft worthy the memory of America's first naturalist, and, while confident that this amount will be forthcoming, desires to have interest taken in the project by scientists in all departments in all portions of the country.

-Prof. A. H. Worthen has recently secured by purchase for the State Museum of Illinois four collections of Carboniferous fish teeth and spines, aggregating about two thousand specimens, which probably cannot be duplicated on this continent. It will be arranged for exhibition in the course of two or three months.

-Dr. M. E. Wadsworth has resigned the professorship of mineralogy and geology in Colby University, and has accepted the directorship of the Michigan Mining School. His address now is Houghton, Michigan, U. S. A. Exchanges are especially desired of papers relating to general and technical education, petrography, general and economic geology, mineralogy, crystallography, and meteorites.

-Professor Forbes's address, "The Lake as a Microcosm," has been printed in the Bulletin of the Peoria Scientific Society for 1887. In it are given generalizations based upon Dr. Forbes's investigations of the lakes of Illinois and Wisconsin.

—Prof. A. F. Marion, of Marseilles, has been elected a corresponding member of the Department of Anatomy and Zoology of the Academy of Science at Paris.

-Dr. H. Mayr, of Munich, has been appointed to the professorship of botany in the University of Tokio.

-Dr. Oscar Hertwig has been appointed ordinary professor of anatomy at Berlin, and Dr. G. Volkens has become a privatdocent in botany in the same university.

-Dr. A. Vöchting, of Basle, goes to the chair of botany in Tübingen.

-RECENT DEATHS.-Olry Terquem, student of Foraminifera, at Passy, aged ninety years; Dr. G. Grewink, Professor of Mineralogy at Dorpat, June 30, 1887, aged sixty-nine; Prof. L. G. de Koninck, the veteran palæontologist, at Lüttich, July 15, aged seventy-nine; Julius von Haast, the New Zealand geologist, aged sixty-two years.