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women for degrees in the university. The Cambridge University Syndicate appointed to consider the question is divided in opinion; half have reported in favor of admission to full membership, and half in favor of a separate university at Cambridge.

DR. DAVID KINLEY, professor of economics and dean of the graduate school of the University of Illinois, has been elected president to succeed Dr. Edmund Janes James.

DR. LAUDER W. JONES, dean of the School of Chemistry and also of the College of Engineering and Architecture of the University of Minnesota, has accepted an appointment as professor of organic chemistry at Princeton University.

ALICE M. BORING, of the Peking Union Medical College, China, has been appointed assistant professor of zoology at Wellesley College, beginning with the academic year 1920-21.

DR. ELLSWORTH D. ELSTON, of Cornell University, has been appointed assistant professor of geology at Dartmouth College.

ASSOCIATE PROFESSOR J. WEMYSS ANDERSON, has been appointed to the recently established John William Hughes Chair of Engineering Refrigeration at Liverpool University.


TO THE EDITOR OF SCIENCE: I regret that in my criticism (SCIENCE, March 26) of Professor Hathaway's exposition of differentials (SCIENCE, February 13) I was led by an unwise desire for brevity into making a statement which, in its unqualified form, will not stand analysis. The statement that "lim Nay is inevitably zero" is certainly not true unless N remains finite, and Professor Hathaway is quite justified (SCIENCE, May 7) in chiding me for this error, since his N is not restricted to finite values.

At the same time I can not feel that I was essentially mistaken in contending that his presentation of differentials "would prove highly misleading to the modern student."

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It is true that when he defines the differential dy as the limit of NAy for lim Ay== 0, he does allow the multiplier N to vary (as I should have stated); but it is also true that he gives no indication whatever as to the manner in which N is to vary; and without some such indication his limit of NAy, and hence his differential, dy, remain wholly undefined!

On page 167 (I quote verbatim this time, to avoid the danger of renewed injustice), his formal interpretation of differentials is given as follows: they are "ordinary arithmetical increments, but in a variation defined as in the first ratio, or as the variables begin to increase, or, in the instantaneous state, which are all one."

I maintain that such vague statements are not likely to convey to any student's mind " a rigorous theory, neglecting no quantity, however small, leaving no unexplained symbol." They are much more likely to leave him with the traditional impression that differentials are really as Bishop Berkeley called them, the "ghosts of departed quantities," or, in Professor Osgood's phrase, abominable "little zeroes," unworthy of a place in mathematical discussion.

The object of my brief letter was, as stated, not to discuss historical questions (the importance and value of which no one can deny) but merely to contrast the obscurity of Professor Hathaway's presentation with the clearness and simplicity of the modern treatment-the treatment which has been the commonplace of every treatise of recognized standing since the middle of the nineteenth century.



POPULAR SCIENTIFIC LITERATURE TO THE EDITOR OF SCIENCE: In the issues of SCIENCE for February 20 and 27 Mr. F. L. Ransome, of the U. S. Geological Survey, published a most interesting article on the "Functions and Ideals of a National Geological Survey."

In this article, attention was given to the

educational work which such a survey might carry on. To a librarian, his statements are of more than casual interest. He called attention to the dearth of popular literature on certain scientific subjects, especially geology. While other branches of nature study, including plant and animal life, appeal to a wider circle, and have been considered in a large number of interesting and attractive books, the same is not true of geology or of some of the smaller forms of animal life, as, for example, insect and fresh water life.

May I venture to call the attention of some scientists who read your journal to the desirability of some small, well-illustrated and attractively written books on geology, both descriptive and historical; on some of the mineral products, such as iron and steel; on pond life; on microscopy; and on the lives of American scientists and scientific explorers.

A book is now in preparation for publication by Scribner's, "The strange adventures of a pebble." From the announcement, this is doubtless the sort of book which has been needed for some time. In the quarterly booklist of the Pratt Institute Library (which library has made a speciality of literature in this field) for January, there is a carefully selected "List of technical and scientific books for boys." Astronomy is pretty well covered. A fairly good boys' book on chemistry was published in 1918. The two titles on geology are those by Heilprin and Shaler, both rather old; and on physics, nothing better than a reprinted edition of Hopkins, "Experimental science," which could very well be entirely revised or even broken up into two less expensive volumes. Certainly there is need for more books of this sort.

In the same line, may I call attention to the need of having books lists, to be distributed through schools and libraries and printed in an attractive style with an illustrated cover, and giving descriptions of the books? The attention of many young people could be called to science as a life career if means like these were adopted. Another device to this same end would be a series of posters or printed reproductions of exhibits,

showing some of the interesting phases of nature study or science. These could be printed by such a central bureau or by some national scientific society and distributed to be shown in schools and libraries and at Boy Scout and Camp Fire Girls headquarters. JOSEPH L. WHEELER



IN reference to the applications made to the International Commission on Zoological Nomenclature for copies of the rules, the secretary desires to state that the commission has no supply of reprints for distribution. Several years ago, at request of the secretary, Mr. John Smallwood, 524 Tenth St., N. W., Washington, D. C., prepared several hundred mimeographed copies and he still has about 100 on hand. These are sold at a nominal price to cover expense of mimeographing and postage and zoologists desiring copies can obtain them, as long as the supply lasts, by applying directly to Mr. Smallwood.

C. W. STILES, Secretary



THROUGH the courtesy of Mr. E. W. Nelson, chief of the Bureau of Biological Survey. Washington, four vials containing echinoderms taken from birds' stomachs have been sent to me for examination. As I think there are no published records of birds' using echinoderms for food, Mr. Nelson has kindly consented to my stating in SCIENCE the facts revealed by this trivial investigation and certain important inferences which may be made.

Two of the vials contained holothurian-like objects taken from the stomachs of gulls. The appearance and condition of these specimens indicate that they were picked up on the beach dead and more or less damaged. As they are now quite decalcified, they are hopelessly unidentifiable, and it is probable that one at least is not a holothurian.

The contents of the other two vials are of much greater interest. In each case, the material was taken from the stomach of a duck collected at Bayou Labatre, Alabama. One vial contains two small brown holothurians, somewhat damaged but with the calcareous particles in the skin not at all corroded or injured in any way. The condition of these specimens leaves no doubt in my mind that they were swallowed alive by the duck and that they had been in the stomach of the bird but a short time when the duck was taken. These holothurians are unquestionably some species of Thyone, and are very near, if not identical with, Thyone scabra Verrill, of the southern New England coast But Thyone scabra is not known from south of Delaware or from water less than ten fathoms deep. No holothurians of any sort are recorded from the Alabama coast. This duck's stomach therefore reveals the interesting fact that a species of Thyone, possibly scabra but probably distinct, lives in shallow water on the Alabama coast and serves as a part of the diet for bottom-feeding ducks.

The contents of the fourth vial confirms this conclusion and reveals further the notable fact that brittle-stars also serve as food for ducks. The material in this case is in very bad condition and is more or less digested, but the calcareous particles in the fragments of a holothurian indicate it is the same Thyone as in the other vial, though it has quite lost its pigmentation. Besides these Thyone fragments there are numerous armplates of a brittle-star. These are however, beyond identification and one can not even guess the genus, which they represent. The brittle-star was however an individual of moderate size and was certainly not the small and well-nigh ubiquitous Amphipholis squamata. No brittle-star is as yet recorded from the Alabama coast. It is to be hoped that the publication of the results of the collecting done by these two ducks may lead to equally effective efforts by some zoologist on the Gulf Coast.




Morning Session-10 o'clock ARTHUR A. NOYES, Sc.D., LL.D., Vice-president, in the chair

The components and colloidal behavior of protoplasm: D. T. MACDOUGAL, Ph.D., LL.D., director of the Desert Laboratory, Carnegie Institution, Tucson, Arizona, and H. A. SPOEHR. The living matter of plants is composed chiefly of mucilages and albuminous compounds in varying proportions mixed in the form of an emulsion or as a jelly. The molecules of solid matter are aggregated into groups which also include a number of molecules of water. Growth consists of the absorption of additional water to these groups, with more solid material being added at the same time, the process being termed hydration. The resultant increase may be detected by determination of increased dry weight, or measured as increase in length, thickness or volume. More exact studies in growth have become possible by the establishment of the fact that mixtures of 25 to 50 per cent. mucilage and 50 to 75 per cent. albumin show the hydration reactions of cell-masses of plants. It is also found that certain amino-compounds, such as histidine, glycocoll, alanin, and phenyl-alanin which are known to promote growth also increase the hydration of the biocolloids as the above mixtures are called. Following these empirical tests which have defined the character and field of research upon growth, measurements are now being made of the action of various ions or substances upon the components of protoplasm. Thus the strong metallic bases, potassium, sodium and lithium, exert a limiting action on hydration of carbohydrate (agar) in hundredth normal solution according to their position in the electromotive series, potassium being the strongest and reducing swelling most. Rubidium, however, did not take its place at the head of the list in the single series of tests made, for reasons we are not able to describe. At dilute concentrations (0.000, 1N) all these bases promote hydration, an effect also produced by amino-compounds. The inclusion of substances in a liquefied colloid, afterwards dried, produces a hydration effect different from that which results from placing the substance in the water in which the biocolloid may be placed. This fact has wide significance in the physiological action of cell-masses. Renewal or replacement of hydrating solutions may result in pulsations or rapid swellings followed by slow shrinkages or retractions. Gels similar to those entering into living matter may take on structure by which small masses or sections may display

highly differentiated action, increases in size and changes in forms after a manner which presents important possibilities in the behavior of cell-organs.

Respiration: W. J. V. OSTERHOUT, professor of botany, Harvard University. A simple method of measuring respiration has been developed whereby determinations can be made at frequent intervals (as often as once every three minutes). The application of this method to the study of anesthesia shows the incorrectness of the theory of Verworn, according to which anesthesia is a kind of asphyxia, due to the inhibition of respiration by the anesthetic. In the study of antagonism it is found that the antagonistic substances may increase or decrease respiration, but when properly combined they show little or no interference with normal respiration. The study of the action of acids and alkalies shows that these substances may increase or decrease respiration and that the effect varies greatly with different organisms.

The behavior of the sulfurea character in crosses with Enothera biennis and with Enothera franciscana: BRADLEY M. DAVIS, professor of botany, University of Michigan.

Enothera funifolia, a peculiar new mutant from Enothera lamarckiana.

A third duplication of generic factors in Shepherd's purse: GEORGE H. SHULL, Ph.D., professor of botany and genetics, Princeton University. In the third generation of a cross between a wild biotype of the common shepherd's-purse (Bursa bursa-pastoris) from Wales and Heeger's shepherd's-purse (B. Heegeri) there appeared a small number of plants of unique type, having a more coriaceous texture than in the plants of either of the two original strains involved in the cross. This new type has been designated coriacea. It differs from the common form, not only in texture, but the lobing of the leaf is reduced and simplified and the angles of the lobes are almost spinescent. The proportion of coriacea to the typical sibs in this F, family was 12: 187 or almost exactly a 1:15 ratio. This suggested at once the presence of two independently inherited factors for the normal texture, the coriacea type being produced only when these two factors K and L were absent. Subsequent breeding has shown that coriacea breeds true when selfed, and has also confirmed the interpretation of this as a third case of duplication of factors in this species. The two characters previously shown to be thus constituted are the triangular form of capsule, and the division of the leaf to the midrib which brings to light the char

acteristic lobing found in the form designated rhomboidea The duplication of the capsule determiners is practically universal while that of the leaf-lobe factor is less frequently found. Studies on the coriacea character are still too limited in extent to justify a statement as to the prevalence of duplication of the factor for the usual texture of the leaves.

Some effects of double fertilization in maize: EDWARD M. EAST, Ph.D., professor of experimental plant morphology, Harvard University.

The chemistry of the cell: THOMAS B. OSBORNE, Ph.D., Sc.D., research chemist, Connecticut Agricultural Experiment Station. (Introduced by Dr. Harry F. Keller.)

The relation of oxygen to charcoal: GEORGE A. HULETT, Ph.D., professor of physical chemistry, Princeton University.

Products of detonation of TNT: CHARLES E. MUNROE, Ph.D., LL.D., professor of chemistry, George Washington University, and S. P. HOWELL. TNT has not only proved a most efficient explosive for war purposes but, following the advice of the Bureau of Mines, the surplus has been now used in large quantities on various public projects with remarkable success, thus completely disproving the opinions given in various quarters following the armistice that it was unfit for industrial use, dangerous to store, and should be thrown away. Notwithstanding the success attained it is believed that with a more complete knowledge of its behavior even better results in its use both for military and industrial purposes could be attained. It is particularly desired to know the kind and quantities of products it yields on explosions. These are known broadly but it is also now known that they vary with the different conditions under which the TNT is exploded and this study has been made to gain more precise information regarding these conditions. It is already known that among the products are considerable quantities of carbon monoxide, hydrogen and some hydrocarbons, such as methane, together with free carbon in a soot-like form. Hence TNT is not suitable for use in underground work or close places because the gas evolved is poisonous and inflammable and can form explosive mixtures with the atmosphere in these close places.

A new map of the vegetation of North America: JOHN W. HARSHBERGER, Ph.D., professor of botany, University of Pennsylvania.

On the vibrations of rifle barrels: ARTHUR GORDON WEBSTER, Sc.D., LL.D., professor of physics, Clark University.


Afternoon Session-2 o'clock

HAMPTON L. CARSON, M.A., LL.D., vice-president, in the chair

Symposium on Psychology in War and Education Introduction: LIGHTNER WITMER, Ph.D., director of the Psychological Laboratory and Clinic, University of Pennsylvania.

Methods: J. McKEEN CATTELL, editor of SCIENCE. The speaker reviewed the development of experimental and quantitative methods in psychology, and especially the transfer of its main concern from introspection to the study of individual differences in behavior. This has made possible the applied psychology which was of such service to the nation in time of war and will prove of increasing value in education and in industry. Efforts to alter conduct by a direct appeal to consciousness, as undertaken, for example, by the churches, the schools and the law courts, have yielded small results. But individuals can be selected for the work for which they are fit and can be placed in the human and physical environment in which their reactions are what we want. By cooperation with other sciences, it is also possible for psychology to change the environment, and behavior can be controlled more effectively by a change in the environment than by a change in the constitution of the individual. The older psychology must be put in its proper place; it can not be altogether discarded. As far as production goes, consciousness may be only a spectator; but it is the ultimate


Psychological examining and classification in the United States army: ROBERT M. YERKES, Ph.D., chairman of Division of Research Information, National Research Council, Washington. (By invitation.) Psychological examining in the United States army was made possible by the prompt action of American psychologists, who individually and collectively, in committees and conferences, formulated plans, prepared methods and induced the army and the navy to utilize psychological service. The methods of examining which were finally adopted are based upon principles previously used but they exhibit also new and important features which constitute significant contributions to the technique of practical mental measurement. The personnel for psychological examining was carefully selected in accordance with qualifications and the men were especially trained at the Camp Greenleaf School for Military Psychology. This intensive training in the rudiments of military sci

ence and military psychology ranks next in importance in its relations to the final success of the service to the superior quality of the army's psychological personnel. The initial purpose of examining was the discovery and prompt segregation or elimination of men of markedly inferior intelligence. The uses which were actually made of results of psychological examinations were extremely varied and covered the classification of men to facilitate military training, the selection of men of superior ability for training as officers or for special tasks, the segregation and special assignment of men whose intelligence was inadequate to the demands of regular military training, and finally the elimination of the low-grade mental defective. It was the demonstration of values in these and several other directions that converted military skepticism concerning the serviceability of psychology into belief and active support. After the official trial of methods approximately 75 per cent. of the officers concerned believed that they should be used further. On the signing of the armistice 90 per cent. of the officers of the army, if we may judge by the opinions of the commanding officers of camps and divisions, were highly favorable to the psychological service.

The relation of psychology to special problems of the army and navy: RAYMOND DODGE, Ph.D., professor of psychology, Wesleyan University. (By invitation.) To help mobilize the human factors that were needed by the army and navy to win the war, that was the task for which the psychologists of the country were organized under the leadership of the National Research Council. Two great achievements stand to their credit; first the sorting of the conglomerate of the draft army with respect to general intelligence under Major Yerkes; and second the discovery, indexing and assignment of trade experience, special skill and presumptive ability to perform the tasks needed by a modern army, under Colonel Scott. These achievements are regarded by experts as an important factor in the supposedly impossible undertaking of building a great fighting organization in a few months time. New demands were made on human nature during the late war, many of which were only imperfectly understood. The task of flying is a good illustration. Psychologists cooperated with the Air Service in studying the effects of high altitudes and in discovering test indicators of the ability to stand them. They were responsible for the mental tests in picking those who could learn to fly with a minimum expense and risk. Gas warfare and adaptation to the wearing of gas masks, the de

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