shall have supervision of the work of conservation. The house amended the bill by authorizing the Illinois Academy of Science to suggest candidates for membership on the board. THE Bellevue Hospital unit, numbering three hundred physicians, nurses and enlisted men, attached to Base Hospital No. 1, at Vichy, near Paris, has received orders to prepare to sail and probably will return at once. Major John H. Wyckoff, secretary of the medical faculty of the New York University and Bellevue Hospital Medical College, who was formerly one of the heads of the American hospital, has received a letter from Lieutenant Colonel Arthur M. Wright, commander of the hospital, in which he said his organization had been relieved and that the hospital had been taken over by an evacuation hospital personnel. The unit is composed of many wellknown New York physicians and nurses from Bellevue Hospital and 200 enlisted men who were recruited at the Medical College for overseas duty. It set sail for France on February 18, 1918, and has since handled a large number of the American Army wounded cases. Base Hospital No. 1 was one of the largest near Paris and received mostly American cases. The organization was prepared for 500 patients but at one time cared for as many as 3,200 cases. The unit includes twenty-six physicians, sixty-five nurses and 200 enlisted men. of electrical engineering and applied mechanics. THE farmers of New Jersey, through their representatives at the annual state agricultural convention at the State Capitol at Trenton, have requested the Legislature to provide an appropriation for a horticultural building at the State College of Agriculture at New Brunswick. THE gift to the University of Caifornia Museum of valuable textiles left by the E. E. Caswell Estate and presented to the university through Regent Phoebe A. Hearst, was acknowledged by the board of regents at the recent monthly meeting in San Francisco. The textiles have been loaned to the Palace of Fine Arts for exhibition. IN the reorganization on the basis of departments at Yale University, Professor B. B. Boltwood has been elected chairman of the university department of chemistry. PROFESSOR GUY WEST WILSON has been appointed associate botanist and plant pathologist in Clemson College, South Carolina. FROM Nature we learn that Dr. R. M. Cavan, of the chemistry department of University College, Nottingham, has been appointed principal of the Technical College, Darlington, and Mr. W. H. Watson, of the chemistry department of the Northern Polytechnic Institute, has been appointed vice-principal and head of the chemistry and natural science department of the Municipal College, Portsmouth. UNIVERSITY AND EDUCATIONAL Ar the commemoration day exercises of the Johns Hopkins University on February 22, Dr. William H. Welch, who presided, announced that a sum of approximately $400,000 had been given anonymously for the erection of a building at the Johns Hopkins Hospital to serve as a woman's clinic. THE present applied science building of the University of Toronto, which has been condemned, will be removed and in its place will be erected a large engineering building. The chemistry and mining buildings will be enlarged and will accommodate the department This metal has already been applied in a number of cases to commercial devices for this purpose, one of which is being manufactured at the present time by the Central Scientific Company. Any increase of sensitiveness, or any reasonable amount of force on a given temperature change may be obtained by manipulation of the length, width and thickness of the metal. By using very thin sections extreme sensitivity may be obtained, deflections as great as one fourth inch per degree Centigrade being possible. On the other hand, by materially increasing the thickness great force can be created, in one instance approximately one fourth pound per degree Centigrade. On account of the process of manufacture employed, the danger of permanent set has been practically eliminated, so long as the metal is not overstrained, G. E. Thermostatic Metal, as it is known to the trade, is produced regularly in thicknesses from .015 to .25 inch; widths up to 6 inches and lengths up to 36 inches. In special cases it may be obtained in thickness as small as .005. I feel sure that a knowledge of the characteristics and adaptability of this material will enable many experimenters to solve problems of temperature control or indication with much greater ease and accuracy than heretofore. CHESTER I. HALL GENERAL ELECTRIC COMPANY, COMMON NUMERALS THE origin of our common number symbols has never been clearly established, but until recently all writers on this subject agreed that these symbols were transmitted to Europe by the Arabs who had obtained them from India. This is the view expressed in the general encyclopedias and in our mathematical histories which consider this question. For example, in the eleventh edition of the Britannica under the word "numeral" there appears the following statement: The areas designated by states appear in the following table: What is quite certain is that our present decimal system, in its complete form, with the zero which enables us to do without the ruled columns of the abacus, is of Indian origin. From the Indians it passed to the Arabians, probably along with the astronomical tables brought to Bagdad by an Indian ambassador in 773 A.D. are In view of these facts it is very interesting to note that during recent years available data relating to the origin of our common number symbols have been carefuly reexamined by Carra de Vaux, who published in volume 21 of Scientia a brief summary of his results. Among the most surprising of these results number the following: Our common symbols originated in Europe and from there were transmitted to the Persians. Both India and Arabia received them from Persia, so that the common term Hindu-Arabic numerals is decidedly misleading. The common numerals did not come from letters of the alphabet, but were formed directly for the purpose of representing numbers. It does not appear likely that all of these conclusions reached by Carra de Vaux, who has made an extensive study of the intellectual life among the Mohammedans, will be at once accepted, but they tend to exhibit the weak foundation upon which the history of our common numerals has thus far rested. In fact, the nature of this question is such that it seems likely that general agreement as regards the origin of our numerals can result only from that attitude of mind (known as philosophy) which would rather accept as facts what can not be proved than acknowledge ignorance. Conclusions similar to those of Carra de Vaux were also expressed in a Russian work by N. Bubnow (1908), which was translated into German and published in Berlin in 1914. G. A. MILLER PSYCHOLOGICAL RESEARCH FOR AVIATORS TO THE EDITOR OF SCIENCE: In his article on "Psychological Research for Aviators" in SCIENCE of January 24 Dr. Dunlap inadvertently neglects some of the most important work on tests of flying ability. Burtt, Troland and Miles were working at Cambridge in the spring and summer of 1917, and the work of Captain Henmon at Kelly Field No. 2 in the spring of 1918 was contemporaneous with and under the same authorization as that of Professor Stratton. A prophesy based upon Captain Henmon's results was of notable influence in leading the director of military aeronautics. to authorize tests of ability to learn to fly in connection with the regular work of the examining boards. E. L. THORNDIKE TEACHERS COLLEGE, COLUMBIA UNIVERSITY TO THE EDITOR OF SCIENCE: Professor Thorndike has called my attention to the fact that in my article on psychological research for aviators in SCIENCE of January 24, I made no reference to the work of Burtt, Troland and Miles, and the work of Henmon, which was reported in relatively full detail in Thorndike's article in the preceding (January 17) number of SCIENCE. A footnote referring to Thorndike's report should have been inserted in my article to prevent the supposition that I was covering the work of all investigators. No detailed information concerning the work of Burtt, Troland and Miles was given me until Thorndike's address appeared, hence I should not attempt to describe it. The work started by Stratton, and subsequently developed by Stratton and Henmon, should, as I stated in my article, be reported by Stratton. I may add that important work in aviation was done by a number of psychologists not mentioned by either Thorndike or myself: Maxfield for instance conducted a valuable piece of research which was, I believe, reported to the psychology committee. I trust it will be understood that my report was not intended as a comprehensive account of all work in aviation by psychologists, and that if I am able, later, to give a full account of all work done under my control, I shall not attempt to relate the activities of other psychologists except in so far as those activities had direct effects in facilitating or interfering with my own work. KNIGHT DUNLAP QUOTATIONS THE HISTORY OF INFLUENZA ALTHOUGH the term influenza was not formally adopted by the Royal College of Physicians of London till 1782, the disease was known to Hippocrates and other ancient physicians, and a formidable list of epidemics in various parts of the world between the years 1173 and 1875 is given by Hirsch in his "Handbook of Geographical and Historical Pathology." Records of outbreaks in this country between 1510 and 1837 were collected by Theophilus Thompson and published by the Sydenham Society in 1852; they were brought down to 1891 by E. Symes Thompson. Many physicians, among them such men as Sydenham (1675), Huxham of Plymouth (1729), Arbuthnot (1732), Sir George Baker (1762), and John Fothergill (1775) had written about the disease from the clinical point of view, but Immanuel Kant, who, like Bacon, took all learning for his province and was specially interested in medicine, was one of the first to direct attention to its epidemiology. Towards the end of the eighteenth century influenza swept over nearly the whole world. It reached Siberia and Russia, China and India, in the autumn of 1781, and in the following December and February it invaded successively Finland, Germany, Denmark, Sweden, England, Scotland, the Netherlands, France, Italy, and Spain. Kant, in a "Notice to Physicians" published in the lay press of Königsberg on April 18, 1782, considered the disease in its relation to physical geography. He expressed the opinion that it was spread not only by atmospheric conditions but by infection conveyed by insects. The paths of communication between Europe and other parts of the world by sea and by caravan were, he thought, the means of conveyance of many diseases, and he found reason to believe that the Russian trade route to China by land had brought several kinds of harmful insects from the farthest East. The epidemic of 1781-82 spread along the Baltic coast till it reached Königsberg; thence it travelled to Danzig and Prussia. Kant's interest in influenza is shown by the frequency with which he refers to the subject. With the object of procuring further information he sent his "notice" to Russia, and from Baron von Asch, surgeon in the Russian army, he learned that in January, February, and March, 1782, a disease described as "febris catarrhalis epidemica benigna" prevailed in the Russian capital. It originated in eastern Siberia, on the Chinese frontier, and spread through the whole of Russia. -The British Medical Journal. SCIENTIFIC BOOKS A Text-book of Precious Stones. By FRANK B. WADE, B.S. Published by G. P. Putnam's Sons, 1918. 8vo, pp. xiii + 318. Illustrated. Those who are familiar with the work on "Diamonds" by the same author will find the present book characterized by similarly attractive features. The style is clear and precise and readability and practicality are afforded by examples drawn from the writer's own experience. The book will appeal to the amateur rather than the professional student, but this is probably the intention of the author. His experience as a teacher has doubtless aided him in presenting the subject in a systematic and easily assimilable manner. The physical properties of gems are treated under the various subdivisions of refraction, absorption and dichroism, specific gravity, luster, hardness, and color, each to the extent of one or more chapters, and numerous practical details are given in the chapters on testing, cutting, occurrence and imitation of gems. The chapter on "tariff laws" affords useful information not readily found elsewhere and the bibliography of the subject of gems is the most complete and satisfactory for the purposes of the general reader that the reviewer remembers to have seen. The book is not extensively illustrated, a few text figures from line drawings comprising all the pictures that are provided. Besides its usefulness for general reading, the title of the book and its systematic plan suggest that it could be employed for more formal instruction. The wide distribution of gems in Nature and their possession in some form in almost every home, make it probable that they could be used more extensively than is now the case as a basis for school study. The reviewer finds little to criticize adversely in the book beyond the occasional use of the term "gemology." While this term might be generally understood to refer to the science of of gems, it is incorrectly formed for this purpose and in reality has quite a different meaning. The Greeks seem to have had no single term for distinguishing objects used for the purposes for which we use gems, but indicated things of value by the adjective Tivos. Prefixing this adjective to Xíos, stone, the term tiniolithology can be obtained, which is at least a word properly formed to indicate the science of gems. OLIVER C. FARRINGTON FIELD MUSEUM OF NATURAL HISTORY SPECIAL ARTICLES PINK ROOT OF ONIONS IN 1915 Professor F. W. Mally called the writer's attention to a very serious disease of onions in Webb County, Texas, and locally known as pink root. Investigations were begun on this disease with Professor Mally, who cooperated in the field experiments and offered valuable assistance in many ways. A search in literature showed that there were no records that could be found, where mention was made of this new plant trouble. From conversation with Professor Mally I was told that Professor W. M. Gilbert, of the United States Department of Agriculture, had at one time worked on this disease and also published an account of the same. However, a letter received from Professor Gilbert dated May 15, 1918, says as follows: "So far as I know there are no publications on this disease, as I did not do enough work on it to secure results for publication and have not had the opportunity to study it very recently." The writer was the first to report on this disease in 1917.1 1 Taubenhaus, J. J., "Pink Root, a New Disease of Onions in Texas," Phytopath. 7: 59, 1917 (abstract). The symptoms of this trouble are very striking. Affected roots turn yellowish, then pink and dry up. The disease is confined to the roots only and not to the bulb. As fast as the old roots are affected new ones are produced, these in turn becoming diseased. In the end, the bulb spends all its energies in producing new roots which in turn become affected, thus failing to attain the commercial standard. Diseased bulbs remain dwarfed and small to the end of the season, although apparently sound in every other way. The average annual loss from this disease in Webb County may be estimated at forty per cent. Careful investigations in the laboratory of the Texas Experiment Station revealed the fact that the disease was caused by an apparently new pathogenic organism, the name of which is proposed to be Fusarium malli, n. sp. Over one thousand plate cultures were made from diseased material and in nearly every case a pure culture of the above organism was obtained. Moreover in planting healthy onion sets in both sterilized sand or soil in which a pure culture of the Fusarium fungus was worked in, the disease in each case could readily be reproduced. The symptoms on the artificially infected plants were in every respect identical with those of infected plants naturally found in the field. The checks remained free, proving that Fusarium malli Taub. is the cause of pink root. Numerous laboratory experiments, which were duplicated in the field have yielded results which are briefly summarized as follows: 1. The disease is carried with infected sets. 2. The disease is carried over from year to year in the soil. Short term rotations with other crops than onions on pink root lands do not starve out the pink root fungus. 3. Pink root attacks not only the onions but also the garlic and the shallot. It does not seem to attack any other of the liliaceous plants. 4 Steam sterilizing will kill the fungus in the soil. Formaldehyde at the rate of one pint to twenty gallons of water, per square foot will also rid the soil of the causal organism. 5. Applications of lime will not rid the soil from pink root. 6. In infected soils liberally fertilized, especially where quickly available plant food is applied, together with proper cultural management, the crop can be nursed to produce fairly normal yields. In this case the proper fertilizer merely stimulates the bulbs in producing new roots faster than the disease can destroy them. 7. Fertilizers rich in nitrogen and organic matter are especially valuable for use in soils infected with the pink root. 8. Healthy sets when planted on diseased soils will contract the disease. Likewise, diseased sets planted on healthy soils will also yield diseased bulbs. Numerous experiments both in the field and in the laboratory are still in progress and as soon as these are completed a bulletin will be published by the Texas Experiment Station giving a full description of the causal organism and results of the experiments. J. J. TAUBENHAUS COLLEGE STATION, TEXAS A CHROMOSOME DIFFERENCE BETWEEN THE SEXES OF SPHÆROCARPOS TEXANUS THE chromosome group in the cells of the female gametophyte of Sphærocarpos texanus is characterized by one large element greater in length and in thickness than any of the other chromosomes in the group. This large element does not appear in the chromosome group of the male gametophyte, but instead there is a small chromosome commonly nearly spherical in form, and unlike anything found in the female. The other chromosomes in the cells of both sexes vary in length. They have the form of rods, usually curved. The chromosome number for each sex seems to be eight. In the cells of the female, seven of the eight are similar respectively to seven of the male. The eighth chromosome of the female (the largest one) seems to correspond to the small chromosome of the male. The condition as to the chromosomes of the gametophytes in |