Smith have been promoted to professorships of mathematics at the University of Cincinnati.

NEW appointments have been made to the medical staff of Dalhousie University as follows: Dr. R. P. Smith, of Edinburgh and Durham, has been appointed professor of pathology and bacteriology and fills the vacancy created by the resignation of Dr. A. G. Nichols; Dr. G. S. Eadie, of Toronto, who has spent the past two years at the biochemical institute of Cambridge University, has been appointed assistant professor of physiology; Dr. Elizabeth Smith Bean, formerly of the University of Wisconsin, has been appointed instructor in histology and embryology. Dr. Howard A. Jamison, of Glasgow, comes to the university as assistant in pathology and bacteriology, and G. A. Grant fills a similar position in the department of biochemistry.

HAROLD B. PIERCE has resigned as Fleischmann research fellow at the University of Rochester and has again assumed his duties as associate professor of dairy and food chemistry in the department of agricultural and biological chemistry at the Pennsylvania State College.

DR. PERRY YATES JACKSON, instructor in physiological chemistry at the University of Chicago, has been elected to a professorship in the department of chemistry at Park College, Mo.

DR. WILLEM JACOB LUYTEN, astronomer at the Harvard College Observatory, has been promoted to assistant professor of astronomy.

NEW appointments in the college of engineering and architecture at the University of Minnesota include C. A. Hughes and J. A. Wise, assistant professors of structural engineering. Mr. Hughes comes from the University of Toronto and Mr. Wise from the Corps of Civil Engineers of the U. S. Navy.

AT Lafayette College, Ernest M. Fernald, of Cornell University, has been appointed assistant professor of mechanical engineering and Anson W. Voorhees, assistant professor of geology.

AT the University of Buffalo, Dr. George Claude Hicks has been appointed assistant professor of biology; George E. Read, instructor in physics, and Dr. Reginald Pegrum, instructor in geology.

DR. M. A. GRAHAM, associate professor of chemistry at Mills College, has been appointed professor of chemistry at the Dominican College of San Rafael.

DR. PAUL A. MURPHY, formerly head of the plant diseases division, Department of Agriculture, Irish Free State, has been appointed to the newly created professorship of plant pathology in University College, Dublin.

DISCUSSION AND CORRESPONDENCE

EXIT THE TENTAMEN, BUT...

DR. HOLLAND in his recent letter to SCIENCE (July 1) has noted the decision of the International Commission on Zoological Nomenclature that that twopage work was not published, but was intended as a circular letter. He does not mention, however, that the names involved are not thereby eliminated, but are merely thrown back on later publications, and is entirely silent on the extraordinary confusion that will result from the fact that these later concededly valid uses are in general incidental, rarely naming a type or indicating the intended contents of the genera, or in any way defining them save by citing some one or more species as belonging to them.

For instance, take Limnas, whieh Dr. Holland mentions. In 1806 it appears in the Tentamen with the well-known species chrysippus (Linnaeus). Then in the period 1806-1816, but at dates that are not more exactly known, Hübner figures 16 species of Limnas in the "Sammlung Exotischer Schmetterlinge," thereby firmly fixing the name in a work that every one agrees is published. Incidentally a prospectus in our library shows that 15 Limnas were

published in March, 1814. After that he abandons the name, and bases his binary nomenclature (which now becomes strictly binomial) on a series of "coitus" names, from the "Verzeichniss," which began to be published at that time. Later Boisduval on a plate of the Buffon Series, figures a Limnas pixe, belonging to a group which is not related to chrysippus L., but which is related to forms which Hübner excludes from Limnas. The corresponding text was never published. Then the question rises: Is the type of Limnas the first species published in the "Sammlung," which is now unknown, but may be fixed any time by the discovery of a new dated advertisement of the "Sammlung" or does the ghost of the "Tentamen" fix it to chrysippus as soon as valid publication occurs? or does it become pixe, a species which Hübner did not know? or do we reject all this, and hunt for the first attempt at a formal founding of the name, all these uses being in a sense incidental and assuming that the Tentamen had established the name? or finally do we adopt the name from Hübner's "Systematisch-Alphabetisch Verzeichniss" of 1822, which every one admits was published, but which so far as I can find no one in America has seen? And in the last case does the name actually appear there? Some one in Europe who has a copy will have to answer that. Meanwhile what shall we do with the Danaids of the chrysippus group and the Erycinids of the pixe group?

Again, take Coleophora, which was in universal use for the best part of a century, and which is still in

Nine tenths of the Tentamen names are now left him in similar states of uncertainty. What would Dr. liet Holland do about it?

迎

Confusio Incidentally I note an error or two in Dr. Holland's erstatement. As to the Tentamen being unused until Scudder recovered and reprinted it, it (or the names oft in it) was used by Hübner himself in the "Sammlung Exotischer Schmetterlinge" (for ten years), and it is said in the "Systematisch-Alphabetisch Verzeichniss," Hol his last formal lay-out of the system; also by Ochsenat heimer and Treitschke, Stephens, Herrich-Schaeffer, Zeller, Boisduval, Curtis and T. W. Harris. None hat of these authors adopted all the names, as the law of priority was not strictly construed in those days; also most people then did not feel the need of so many genera. Ochsenheimer specifically mentions the Tentamen, and Harris refers to Apatela as in common use. Others cite "Hübner" as author. Hübner himself says it was "partly accepted and partly rejected"-a true statement.

PARASITIC COPEPODS

IN the Sitzungsberichte of the Vienna Academy of Science there recently appeared (vol. 133, p. 613) a paper by Helene Kurtz upon two new parasitic copepods. The first of these new species belonged to the genus Achtheinus, and in dealing with it a question as to the validity of the genus was raised. This question was decided in the negative and it was stated that Achtheinus must be regarded as a synonym of Dana's much older genus Lepidopus. Such a conclusion might seem legitimate at first, but if we follow the steps by which it was reached we realize that the mode of reasoning employed is very defective.

In Dana's genus the first legs were uniramose and 3-segmented, the second, third, and fourth legs were biramose, the rami of the second pair 2-segmented, of the other pairs 1-segmented and rudimentary; the terminal segment of the maxillipeds was flattened

into a broad lamina covered with scales, but without a claw. In Achtheinus on the contrary all four pairs of legs are biramose, the rami of the first 3 pairs 2-segmented, of the fourth pair 1-segmented; the maxillipeds have an ordinary terminal segment, with a stout terminal claw, but without scales.

Dana's type specimen has long since disappeared and no others have been obtained that could be identified with it, and hence it is impossible to verify or disprove his genus by any reexamination of specimens. In such a case the validity of the genus must rest upon the original description and the figures illustrating it. Fortunately both of these in the present instance are clear and decisive. Dana recorded the first legs as uniramose, and his figure showed a distinctively uniramose and 3-segmented leg, bearing no resemblance whatever to the first legs of Achtheinus, nor to either ramus of those legs. In the second legs also the basipod is long and narrow and extends out laterally, with the two rami fastened to the outer end, a very different type of leg from that found in the second pair of the genus Achtheinus.

If Dana's genus is to be accepted at all, it must be given these exact details which he described. and figured, and nothing can be added to them or subtracted from them. Especially is there no opportunity for conjectures or hypothetical inferences.

Stebbing in discussing South African Crustacea in 1918 (Annals South African Museum, vol. 17, part 1, p. 41) fully recognized these facts. Although he did suggest that the first legs of Dana's specimen "might easily have lost one of the branches in the process of dissection," he nevertheless adopted the genus name Achtheinus and added "the merely conjectural identity of Lepidopus may stand aside."

Miss Kurtz must have failed to understand Stebbing's attitude in the matter for she adopted his suggestion but ignored his real conclusion. Furthermore she carried the suggestion farther than he did by declaring that he had said that the endopod of the first legs in Dana's specimen was probably (wahrscheinlich) broken off. With this for a premise she argued that if the basal segment in the first legs of Dana's genus be regarded as the basipod, the other two segments would correspond to the exopod of the first legs in Achtheinus. And if we could find that "probably" broken-off endopod, and if it should prove to be 2-segmented when we did find it, then the first legs of the two genera would be similar. She considered this sufficient proof of the identity of the two genera and made Achtheinus a synonym of Lepidopus.

She disposed of the scaly covering of the terminal segment of the maxillipeds, which Dana used as the basis of his genus name, by saying that no such

structure had ever been found in the entire order of copepods, and hence Dana must have been mistaken in what he thought he saw. Steenstrup and Lütken described and figured a similar structure in the maxillipeds of their new genus Perissopus (Kongelige Danske Vidensk. Selskabs Skrifter, ser. 5, vol. 5, 1861, pl. 12, fig. 25), and there is every reason for believing the structure in both genera to be genuine.

Absolutely hypothetical reasoning like that quoted above can have but little influence, and it certainly does not possess sufficient merit to prove or disprove the validity of any genus.

DEPARTMENT OF EDUCATION, WESTFIELD, MASS.

CHAS. B. WILSON

NEW DUST TREATMENTS FOR OATS SMUTS SINCE the introduction of copper carbonate for wheat bunt control (Darnell-Smith, and Ross, 1919)1 considerable interest has been shown in dust treatments for grain smuts. It was found by one of us (Thomas) in field tests in 1924 that copper carbonate alone was not effective in controlling oats smuts. However, when one part of either copper carbonate or copper sulfate was mixed with two parts of mercuric bichloride the dust was effective. These mixtures are too expensive for general use even though rapid and easy of application. Other tests showed that the mixture was less effective when inert fillers were added. In 1926 a mixture of one part of copper sulfate, one part of mercuric bichloride and one part of cresylic acid was found to control oats smuts. While the cost of this dust was only about half that of the copper sulfate-mercuric bichloride dust, yet it is also too expensive for general use.

None of these dusts, although they gave satisfactory control of oats smuts, was as cheap as the liquid formaldehyde. This liquid treatment is objectionable because of the difficulty in handling the wet grain and the possibility of seed injury. Since formaldehyde is so effective against smut, and the wet methods of grain treatment are objectionable, an attempt was made to put formaldehyde in a dust form. This was done by mixing 40 per cent. formaldehyde with either infusorial earth or charcoal. These dusts stick well and thoroughly coat the grains when mixed with them. In these tests dusts containing 9 per cent., 15 per cent. and 25 per cent. of 40 per cent. formaldehyde were used, each at the rate of 3 ounces per bushel

1 Darnell-Smith, G. P. and Ross, H. A dry method of treating seed wheat for bunt. Agr. Gaz. N. So. Wales 30: 685-692, 1919.

2 Thomas, Roy C. Dust treatment for smut in oats. SCIENCE, No. 1567, Vol. LXI: 47-48. January 9, 1925.

of grain. While the checks showed 47 per cent. smut the various formaldehyde dusts reduced smut to less than one per cent.

Another new treatment, iodine vapor dust, was tried in these same experiments. This dust was made by mixing finely ground solid iodine with infusorial earth. The iodine vaporizes readily at ordinary temperatures and diffuses through the infusorial earth giving it a light yellow-ochre color. This dust contained 5 per cent. by weight of iodine and was applied at the same rate as the formaldehyde dust. Only three smutted heads were found in three one-hundredth acre plots which were treated with this dust. It is possible that lower concentrations of iodine dust will also control the oats smuts. Further tests are under way. The cost of treating grain with these dusts is estimated at considerably less than 5 cents a bushel.

J. D. SAYRE R. C. THOMAS

OHIO AGRICULTURAL EXPERIMENT STATION, WOOSTER, OHIO

It

DO CATS SHARPEN THEIR CLAWS? LAST winter the family cat (castrated male, 32 years old) shed a number of claws in the house. These were found during January and February, some of them split lengthwise, the others intact. struck the writer that the shedding of claws is probably a normal phenomenon with cats comparable to related phenomena, as that of the shedding of horns by deer. If this were true, it might be expected that some of the claws would be left in the bark of those trees which the cat used regularly for scratching. Upon investigation in April this bit of evidence was found in the form of two halves of a claw stuck into the bark of an elm and several halves lying under different trees used by the animal. The section of the bark was cut from the tree and with the pieces of claws has been mounted and placed in the college zoological museum.

This is but an isolated observation. There are good grounds, however, for believing the conjectured explanation to be correct. Cats do not instinctively or from experience select good grinding surfaces, slightly rough and hard, such as a cement walk, the foundation stone or the corner boards of a house, or smooth hard posts. They make use of the rough bark of trees which is always much softer than their claws. Observations of their scratching movements show that the animals do not scrape downward over the surface of the object, but catch the claws into the surface and with a circular stroke pull first downward and then outward and slightly upward. Careful examination of the cat's paws each time when a

claw was found failed to reveal any sign of injury. It was impossible to identify the toe from which the claw had dropped. This strikes the writer as fair proof that the shedding of claws is a normal phenomenon. The claws of the rear feet are possibly lost as they become loosened, or they may be pulled out by the animal with his teeth. Cats are frequently seen to pull at their hind claws in a manner suggesting this.

The shedding of claws is most likely seasonal, as are the related phenomena in other animals. Why then should the cat carry on the scratching movements throughout the year? It is possible that a further function of the scratching may be that of keeping the claws from curving too much, consequently growing into and irritating the paw. The irritation caused by claws which are curved too much or by the itching or other annoyance of loose claws may be the stimulus that starts the scratching movements. In this connection a colleague, a zoologist, has called attention to a reaction of badgers. These animals frequently drop out of an intense fight, roll over on their backs and scrape the claws of their front paws by rapidly drawing the paws across each other, pads facing. In accounting for the continuation of the scratching activity throughout the year, however, the likelihood of this being a habit reaction must not be overlooked.

DEPARTMENT OF PSYCHOLOGY, BELOIT COLLEGE

OLE N. DE WEERDT

RECENT PUBLICATIONS OF THE NATIONAL RESEARCH COUNCIL

Two recent publications in the National Research Council's Bulletin Series should be of rather wide interest among scientific men. One (Bulletin 58) is entitled "Handbook of Scientific and Technical Societies and Institutions of the United States and Canada." The American section of this bulletin was compiled by Clarence J. West and Callie Hull, and the Canadian section by the National Research Council of Canada. The other (Bulletin 60) is entitled "Industrial Research Laboratories of the United States, including Consulting Research Laboratories, Third Edition." This bulletin was compiled by Clarence J. West and Ervye L. Risher. Both bulletins are the output of the National Research Council's Research Information Service, of which Dr. West is director.

The purpose of publication of the handbook is to present a ready guide to those scientific and technical societies, associations and institutions of the United States and Canada which contribute to scientific knowledge or further research through their activities,

publications or funds. Only those government institutions are included which administer private funds. Organizations directly controlled by universities or colleges have been omitted because it is expected that they will be covered by the forthcoming publication, "American Universities and Colleges," to be issued by the American Council on Education. Seven hundred and nine American organizations and seventy-four Canadian organizations are listed in the bulletin. The address of the secretary, the date of organization, the major object of the institution, the character of membership and amount of dues, time of meetings and information concerning publications are given for each institution.

The bulletin on Industrial Research Laboratories lists 999 such laboratories in the country, giving for each laboratory the name and address of the supporting industrial or commercial concern, the makeup of the research staff, and a list of special subjects to which the research activities of the laboratory are devoted. The first edition of this bulletin was published in 1920 and listed about 300 laboratories; a second edition (first revised edition) was issued in 1921 and listed about 600 laboratories. The present edition (1927) is the second revision of the bulletin.

The difficulties of compilation in connection with both of these publications make it inevitable that some errors, both of commission and omission, have been made by the compilers. The director of Research Information Service (National Research Council, Washington, D. C.) will be glad to have his attention called to any such errors noted by any who may have occasion to examine the bulletins.

NATIONAL RESEARCH COUNCIL, WASHINGTON, D. C.

VERNON KELLOGG

SCIENTIFIC APPARATUS AND

LABORATORY METHODS

PREPARATIONS OF STAINED DECALCIFIED BONE WHICH RIVAL GROUND SECTIONS

GROUND sections of bone, besides being difficult to prepare, are often unsatisfactory for student use either on account of their thickness or due to the fact that they have been mounted in thin xylolbalsam, resulting in the displacement of the air from the lacunar and canalicular spaces of the tissue. It is, however, possible to prepare decalcified bone in such a way that all the advantages of canalicular detail are obtained. Two methods by Schmorl,1 the picro-thionin and the thionin-phosphotungstic acid

11909. Schmorl, G. "Die pathologisch-histologischen Untersuchungenmethoden." Vogel, Leipzig.

methods, give excellent results and the detail demonstrated surpasses that observed in ground sections. With the exception of a few departments of dental histology, neither of these methods is in general use in American laboratories. I have been unable to find Schmorl's original description of his methods but they are repeated in a more recent work of 1909. An excellent discussion of the methods is also found in a paper on the structure of bone of Fasoli2 and adequate directions for the successful use of these methods are given by Carleton3 in his recent book on histological technique. References to Schmorl's methods may also be found in the works of Lange1 and Fischer. It seems unnecessary to completely outline the method since it can be readily obtained in English in a modern text-book on histological technique. Formol, Orth's, Müller's or Regaud's fluids may be used for fixing. Fluids containing mercuric chloride. should be avoided. Best results are obtained with celloidin or frozen sections. If nuclear patterns are desired, the tissue should be first stained in alumcarmine or hemalum, as the success of the picrothionin method depends entirely on the precipitation

of the thionin in the lacunae and canaliculi. The picro-thionin method is best adapted to work with old bone, while the phosphotungstic acid method is more useful for demonstrating the histology of young bone and the process of ossification.

DEPARTMENT OF BIOLOGY,

NEW YORK UNIVERSITY

ALDEN B. DAWSON

SOME FIXATIVES FOR BOTH NUCLEI AND MITOCHONDRIA

A 2.5 per cent. solution of copper bichromate C. P. (Eimer and Amend) has a pH of 2.0. When root tips of Zea are fixed in it the fixation image is that of chromic acid, i.e., the nucleolus appears as a spherical, darkly staining body in a hollow nucleus whose surface is composed of the chromatin reticulum. The mitochondria are either dissolved by the fixative or by the dehydrating alcohol. If, however, a slight excess of cupric oxide is added to the solution, the pH is altered to about 4.6 and the fixation image is greatly changed. There is here no hollow space around the nucleolus; the nucleus is a solid body, and in the resting stages the chromatin reticulum is much

21905. Fasoli, G. "Ueber die feinere Struktur des Knochengewebes.'' Arch. mikr. Anat., Bd. 66, S, 471. 8 1926. Carleton, H. M. "Histological Technique.'' Oxford University Press.

4 1913. Lange, W. "Histologische Zahnärzte." Springer, Berlin.

Technik für

5 1910. Fischer, Bau und Entwicklung der Mundhöhle. höhle.

less distinct. In the dividing nucleus the spireme shows up distinctly and the chromosomes are well preserved. While the spindle fibers are not distinguishable individually, collectively they are well delineated. The mitochondria are well fixed and mordanted and can be followed through each of the mitotic stages. This fixative has the following faults: the resting nuclei show little detail, the cytoplasm is somewhat distorted and the outer layer of cells is generally over fixed. The addition of .05 per cent. acetic acid causes the resting nuclei to show more detail, though one must be cautious in the use of this acid, for a slight excess of copper acetate will dissolve the mitochondria. The most successful formula for the fixative is:

hain's haematoxylin.

hain's haematoxylin. Destaining should not proceed as far as is usual for an examination of the nuclei, for the mitochondria do not hold the stain as well as the chromosomes and can be completely decolorized before the chromosomes have started to fade.

It is very important to make up the fixative at least 24 hours before it is to be used. It must be shaken frequently in the interval and the excess copper oxide allowed to settle. If it is used too soon the fixation image will be that of chromic acid. It is best to wash out the fixative with 70 per cent. alcohol. If the dehydration is too prolonged the mitochondria will be dissolved out of the peripheral cells. A half hour in each of 70 per cent., 85 per cent. and 95 per cent. alcohol, and an hour in each of two changes of absolute, are sufficient for the dehydration.

Another solution which fixes both chromosomes and mitochondria is: