which on the coin is circumscribed by the name METAPEÓN, i.e., of the Megarians, has been published in the United States as representing Euclid the mathematician. This unintentional historical misrepresentation appears in the publication, “A Portfolio of Portraits of Eminent Mathematicians (1896), issued by the Open Court Publishing Company, in Chicago, a firm which in general has done as much as any other in America to advance a sound knowledge of the history of mathematics. The picture of Euclid of Megara is given as that of the mathematician, Euclid. In the memorandum accompanying the picture occurs the statement, "the name Megara is frequently coupled with his [name] on the early portraits as in this case."

The statement just quoted, in so far as it relates to the coin portrait in question, is in conflict with numismatic authority. A specimen of the coin referred to is in the British Museum and has been described by the great authority on coins, Barclay V. Head, who speaks of this coin as follows:2

METAPE N. Bearded head of the philosopher Eucleides of Megara, veiled and wearing ear-ring.

This remarkable type refers to the story that Eucleides attended the lectures of Socrates in the disguise of a woman, the Athenians having passed a decree that no citizens of Megara should be admitted within their walls. (Aulus Gellius, Noct. Att., VI., 10.)

In his catalogue of Greek coins Head3 quotes the Latin passage from Aulus Gellius, the Roman writer of the second century A.D., referred to above, who had studied at Athens. The passage tells the story of Euclid's going to Athens disguised in a "tunica longa "Corolla Numismatica . . . in Honour of Barclay V. Head," Oxford University Press, 1906, pp. 368386.

2"'Historia Numorum, a Manual of Greek Numismatics," by Barclay V. Head, Oxford, 1911, P. 394.

3 ́ ́Catalogue of Greek Coins, Attica-MegarisAegina,' ," by Barclay V. Head, D.C.L., Ph.D. Edited by Reginald Stuart Poole, LL.D., London, 1888, p. 121. See a drawing of the coin in Attica, etc., Plate XXI., 14.

66

muliebri" to attend the lectures of Socrates and of his returning to Megara the next day in the same disguise. In this book Head gives the date of the coin as Cir. 146 B.C. or later"; in his Historia, quoted above, he gives, "Imperial Times?". While Head thus expresses uncertainty as to the exact age of the coin, he entertains no doubt as to the head-dress representing woman's apparel that was worn by Euclid of Megara when on his way to and from the lectures of Socrates.

It is therefore established with as great certainty that this coin does not give the bust of the mathematician Euclid as it is established that this mathematician was not Euclid of Megara.

UNIVERSITY OF CALIFORNIA

FLORIAN CAJORI

RAINBOW BY MOONLIGHT

TO THE EDITOR OF SCIENCE: In connection with the case of the rainbow at night reported by Frank L. Griffin in SCIENCE of March 11, the following case may be of interest: At Burge, Nebraska, a rural post office about eighteen miles southwest of Valentine, on September 4, 1917, at about 9 P.M. a rainbow appeared. The moon had risen about an hour previously and a thunderstorm was coming up in the west, the rest of the sky being clear. A rainbow began to form and it continued to become brighter until a complete arch was formed. It was very distinct, but was nearly white and showed the prismatic colors very faintly if

commercial managing director, and of Dr. Herbert Levinstein as technical managing director, was designed to maintain the interests of both groups, and to benefit the united enterprise by the special contribution of knowledge and experience which each of these gentlemen was expected to make. At the meeting of shareholders in Manchester on Friday last it was announced that Sir Joseph Turner and Dr. Levinstein, while retaining their seats on the board, have been superseded as managing directors by Sir Henry Birchenough, the chairman of the corporation, Sir William Alexander, and Mr. Vernon Clay.

It is no reflection on the new managing directors to express the opinion that the position thus disclosed must arouse grave misgiving amongst all those who recognize the foundation of a self-supporting synthetic dyemaking industry as a matter of the greatest national importance. Disregarding the woeful absence of harmony which appears to be indicated, the aspect of this rearrangement which causes anxiety to chemists is the fact that, at a time when all the scientific knowledge and commercial energy available in this country should be correlated in a concerted effort to establish an industry which, more than any other, depends for success upon the combination of these factors, two of the most experienced practitioners should be removed from very intimate association therewith.

The proper and perfectly natural request for an investigation put forward by the shareholders met with a cold response from the board, and the declaration by the chairmen that a general meeting is not the occasion for an explanation of such peculiar circumstances is one with which many will sympathize; but the public is entitled to full information at the earliest convenient opportunity. Pending more precise knowledge of the facts, it would not be fair to the late managing directors, or to the board, to pass judgment on their action. If, however, as the published statements at present suggest, incompatibility of temperament is the cause, chemists will regard them as having failed in realizing their responsibility to science at a critical

juncture; on the other hand, the board can scarcely escape the reproach of having allowed an impossible situation to continue far beyond the point at which a surgical operation had become an obvious necessity. Having regard to the immense scientific and national interests which are involved in the ultimate success of this enterprise, and to the large sum of public money which has been invested in the corporation, its future conduct demands very careful scrutiny.-Nature.

SCIENTIFIC BOOKS

Practical Plant Biochemistry. By MURIEL WHELDALE ONSLOW. Cambridge University Press, 1920. Royal 8vo, pp. viii+178. Price 15s. net.

It is being recognized by students of the plant sciences that a thorough understanding of plant chemistry is essential to the solution of their problems. This knowledge has been usually obtained, on the one hand, from organic chemistry, and on the other, from plant physiology. It is the gap between these two sciences that this book is designed to fill. The author has made a real contribution to the study of plant chemistry. As in her former book on "The Anthocyanin Pigments of Plants," she has presented a very clear and comprehensive discussion; however, in the few pages of the present volume it is impossible to give more than a cursory discussion of the topic. The book is essentially a laboratory manual, which contains well-chosen experiments that have been tested in practical classes. Through these experiments the student learns to extract from the plant itself the chemical compounds of which it is composed and to understand something of their chemical properties. As an introduction to each chapter, there is presented the fundamental principles and relationships of the particular class of compounds studied in the experiments.

The volume is divided into the following chapters: I. Introduction. The synthesis of the various classes of compounds, and the chemical reactions by which they are brought

about, are discussed. II. The Colloidal State. It is appropriate that the book should begin with this topic, since it is essential for an understanding of the chemistry of cell protoplasm; but this is the least comprehensive and complete of any of the chapters. The two fundamental types of colloidal solutions, suspensoids and emulsoids, are treated and their characteristic properties illustrated. III. Enzyme Action. The underlying principles of enzyme action are briefly discussed and the behavior of different enzymes illustrated by those contained in yeast. The discussion of other enzymes follows in connection with those chapters dealing with the respective substrates. IV. Carbon Assimilation. It is emphasized that chlorophyll is perhaps the most important factor in plant metabolism. V. Carbohydrates and their Hydrolyzing Enzymes. Of all the subjects in plant chemistry which deserve careful treatment it is that of carbohydrates, and to it the author has devoted more space than to any other. There is a careful consideration of the properties and characteristics of the various carbohydrates, their synthesis and relationships in the plant. The monosaccharides, disaccharides and trisaccharides are most thoroughly treated, the latter under the following topics: pentosans, starches, dextrins, inulin, mannans, galactans, gums, mucilages, pectic substances and celluloses. VI. The Fats and Lipases. VII. Aromatic Compounds and Oxidizing Enzymes. The more widely distributed aromatic plant products are grouped: the phenols and their derivatives; the aromatic alcohols and acids including the tannins; the flavone, flavonol and xanthone pigments; and the anthocyanin pigments. The greater portion of the chapter is devoted to the plant pigments and oxidizing enzymes. VIII. Proteins and Proteases. The properties and chemical reactions by means of which the proteins can be detected are studied, and experiments follow which illustrate the method of extraction of the proteins from characteristic grains and seeds. IX. Glucosides and Glucosidesplitting Enzymes. Besides the glucosides of the pigments previously discussed the cyano

phoric glucosides receive chief attention. X. The Plant Bases.

In the preface the author states that the book presents an aspect of plant biochemistry which up to the present time has received very little consideration in teaching. This is not entirely true in America, for at the University of Minnesota there have been offered for several years courses in phytochemistry and biochemical laboratory methods with particular reference to plant products. It is rather a coincidence that the subject matter of our courses should be similar, beginning with the colloidal state of matter and following with the classes of compounds found in plants. These courses through lectures and laboratory have presented to the student the same viewpoint for which this book was designed. Mrs. Onslow is to be commended for her pioneer work in the publication of a text on this important subject. From the mechanical standpoint the book is up to the usual standard of the publications of the Cambridge University Press. It is to be regretted, however, that in all probability the price will prevent it being used in many cases where it could profitably be employed.

CLARENCE AUSTIN MORROW

DIVISION OF AGRICULTURAL BIOCHEMISTRY,
UNIVERSITY OF MINNESOTA

Anthropometry. By ALES HRDLIČKA. Wistar Institute of Anatomy and Biology, Philadelphia. Pp. 163.

Anthropologists and all other workers who have occasion to make use of anthropometry have long been handicapped by the lack of any adequate and up-to-date manual of anthropometry. Now, at length, they have at their disposal a compact and comprehensive treatise on the subject written by one of the most experienced and competent investigators in the field, Dr. Aleš Hrdlička, curator of the Division of Physical Anthropology, U. S. National Museum. As a laboratory manual in physical anthropology and as a handbook for the use of field investigators of physical characters in man, this book should prove invaluable.

The work very properly begins with an annotated translation of the Monaco and Geneva Agreements for the Unification of Anthropometric Measurements. There follows a concise treatment of the preliminaries of the subject, such as preparation, instruments, landmarks, recording grouping of subjects, estimation of age, admixture of blood, pathological conditions, etc. The various topics are handled with clarity and include much original data in regard to general methods. There is a sane appraisal of the various anthropometric instruments and accessories employed in investigations.

The section on the anthropometry of the living deals with a selected list of the most important measurements and observations as determined by the experience of the author. The directions given are very clear and include many practical suggestions tending to promote facility of observation and accuracy of result.

The anthropometry of the skeleton is satisfactorily treated and includes a description of the invaluable system of visual observations elaborated by the author. In the opinion of the reviewer this standardization of morphological observations constitutes a contribution to anthropometric method of first importance, and the section dealing with it might advantageously be expanded. It is to be hoped that Dr. Hrdlička may find time to publish elsewhere a series of articles illustrating the normal or medium development of the various morphological characters and the extremes of their variations. Such illustrations, together with a discussion of the extent and significance of variations, would provide a standard basis for judging the degree of development of immensurable characters. At the present time the value of such observations is dependent upon the accuracy and experience of the individual investigator. It is becoming apparent to physical anthropologists that morphological differences of detail that do not lend themselves to measurement are of primary importance in distinguishing races. Many important functional adaptations be

long also to this category of features which must be described rather than measured.

Perhaps it may be said that the greatest value of this work on anthropometry lies in the fact that it represents the perfected methods of one of the most skilled and best qualified practitioners of the science. Experts may differ as to the value of this or that measurement, or may prefer their own technique in individual cases, but this book is in general reliable and conclusive. A careful follower of its methods can not fail to secure completely adequate physical data in any general anthropometric investigation.

HARVARD UNIVERSITY

E. A. HOOTON

SPECIAL ARTICLES SUBEPITHELIAL GLYCOGEN CELLS IN EMBRYO AND RECENTLY HATCHED FISH

IN April, 1912, while studying the development of the yellow perch (Perca flavescens) I discovered numerous cells filled with glycogen located just below the flat epithelium covering the surface of the embryo. The embryos in which I demonstrated these cells had been developing in the laboratory for twelve days. Upon the addition of a few drops of tincture of iodine to the water in the saucer in which the embryos were contained it was noticed, upon microscopical examination, that there were many round or oval cells, stained a reddish brown, scattered over the surface of the embryo, and especially marked in the fins. I have repeatedly studied these cells in the yellow perch and some other species of fish since I first observed them, and I have found them so interesting that I wish to make a record of some of my findings.

The embryos of the yellow perch are especially well adapted for microscopic examination, as they are exceedingly transparent, and retain their transparency to an advanced stage of development. The development of the eggs takes place rapidly at the ordinary temperature of the laboratory. At the end of the fourth or the beginning of the fifth day after the first division of the egg the embryo begins to make spontaneous movements of its body,

and the rudimentary heart commences to beat. No glycogen cells can be detected at this time, but about the beginning of the sixth day they appear as minute dark brown spots after the application of the dilute iodine solution. The glycogen cells increase in size and become more granular during the further development of the fish. At the time of the appearance of the cells the embryos are covered with a single layer of very thin flat epithelium. The intercellular substance of the epithelial cells can be easily and strikingly stained, after the application of a weak iodine solution and washing in water, by immersing the animal in a dilute aqueous solution of methylene blue for a short time. The blue staining fluid forms a dark precipitate with the iodine in the cement substance, and forms zigzag lines which delimit the cells in the clearest manner. The dark lines may be seen to cross the glycogen cells in many places, indicating that these cells are beneath the epithelial covering.

The glycogen cells are usually more or less elliptical and their dimensions vary with their stage of development. When they first appear their diameters may vary within the limits of 3μ and 10μ. At this time the protoplasm of the cells forms a ring surrounding a large central vacuole containing the glycogen granules. One part of the ring is usually thickened, and contains an elongated elliptical or crescentic nucleus. As the cells enlarge with the advanced development of the fish their vacuoles encroach on the protoplasm until the cells are converted into microscopic sacs of glycogen, in the walls of which a long elliptical or reniform nucleus can usually be found. At this stage the diameters of the cells may be 15μ to 25μ, and the granules, stained a mahogany color with iodine, are chiefly found just below the cell membrane. A number of these granules may coalesce and form a rod-shaped body in the interior of the cell. Sometimes three of the rods unite in the shape of a Y. The stained granules of glycogen dissolve with considerable rapidity in the water containing the preparation, and many of them disappear after a few minutes, leaving the thin cell membrane containing the

nucleus. A very weak solution of iodine formed by adding a drop or two of the tincture to 5 c.c. of water gives the cells their characteristic color in a few seconds if the animal has been removed from the egg envelopes. If the embryos retain their gelatinous envelope they are stained in a few minutes, and it is easy to follow the gradual staining of the cells before the animals are killed by the iodine.

At the time of the first appearance of the glycogen cells there are no blood globules in circulation, but these are first seen a day or two later. At a little later period the liver is formed, and may be stained a brick red by the iodine solution. The liver cells do not contain glycogen granules but are diffusely stained a lighter and more reddish color than the subepithelial glycogen cells.

After a certain degree of development of the fish the number of the glycogen cells becomes gradually lessened by absorption. As I have had the perch under observation for only a limited time after hatching I have never witnessed the complete disappearance of the cells. In and after the third week of development their number becomes much smaller. At that time the glycogen cells of the tail may be crowded into its edge, and those of the pectoral fins arranged in columns radiating in the direction of the striation. This change in position is probably due to the growth of other tissue elements which displace the glycogen cells. In advanced development I have noticed in the tail fin many smaller mesoblastic cells which are not stained with iodine. I have found many glycogen cells, very similar to those of the yellow perch, in recently hatched pike-perch or wall-eyed pike, and in the small-mouthed black bass, but some differences in the appearance of the cells in the different species, and in the solubility of their glycogen granules were noted. The glycogen cells of the pike-perch are coarsely granular, and their glycogen dissolves very rapidly in the dilute iodine solution. The nuclei of the cells are not so apparent as those of the yellow perch. The glycogen cells of the pike-perch may be seen under the