in McGill University, Montreal, to date from October 1. Dr. Macallum will continue his work as chairman of the Research Council until a successor has been named. MR. FLORIAN A. CAJORI, formerly captain in the food section of the Sanitary Corps and on duty in Jugo-Slavia with the American Relief Administration, has completed his graduate work at Yale University and accepted a position as instructor in physiological chemistry at Leland Stanford, Jr., University, in California. PROFESSOR J. T. WILSON, F.R.S., Challis professor of anatomy in the University of Sydney, has been appointed to the chair of anatomy at the University of Cambridge. DR. WILHELM WEIN, professor of physics at Würzburg, has been appointed to succeed Professor Wilhelm Röntgen, who recently retired from the chair of physics at the University of Munich. DISCUSSION AND CORRESPONDENCE THE SPECTRUM OF MERCURY VAPOR TO THE EDITOR OF SCIENCE: In your issue of September 10, Professor C. D. Child calls attention to a greenish glow discharge through mercury vapour whose spectrum shows a continuous band throughout the greater part of the visible spectrum, with the ordinary lines superimposed. This summer, in experimenting on the electrodeless discharge of certain vapors, the writer observed a similar appear ance. The method used was one previously employed by Kowalski.1 A small quantity of mercury was introduced into a highly exhausted Pyrex bulb some 12 cm in diameter. The bulb, surrounded by the primary coil of a Tesla high-frequency outfit, was placed in an electric oven and the appearance of the discharge (if any) observed as the temperature was gradually increased. In common with Kowalski the writer observed two distinct types of discharge. The first, a dazzling white ring discharge occurred at temperatures several degrees above and below 90° C., and showed the ordinary bright 1 J. Kowalski, Physik. Zeit., 15, 225, 1914. line spectrum. The second, a diffuse distinctly greenish glow filling the whole bulb, took place at higher temperatures and was visible until a temperature in the neighborhood of 200° C. was reached. The spectrum of this latter type showed a continuous band with superimposed lines, an appearance similar to that described by Professor Child, but at the higher temperatures only the line 5461 was visible. The writer's observations agree with those of Kowalski, who compares the appearance he observed with an exactly similar one recorded by A. Kalahne.2 Professor Child states that the "radiators" giving rise to the continuous band are uncharged, and suggests that the source of this type of radiation has to do with the formation of clusters of two or three atoms which may be formed when mercury vapor is condensing. Professor Kowlaski ascribes the two appearances noted above to two ionization stages ("Ionisierungsstufe"). It would seem that a possible explanation is the following. At the lower temperatures, because of the greater mean free path, even in the case of an electric field of relatively small intensity, sufficient energy is communicated to an atom on collision to produce ionization. During recombination the line spectrum is emitted. At the higher temperatures, because of the relatively small mean free path (the vapor pressure of mercury at 160° is roughly twenty-five times that at 90°), but little energy is communicated on collision and but little, if any, ionization occurs. The line spectrum accordingly is feeble or absent. Some electrons, however, are displaced from their normal orbits, and in their return to their normal positions, radiation is emitted. Normally such a radiation would also give rise to spectral lines, but we may assume that in the case of the mercury atom with its numerous electrons, the frequent atomic impacts occurring at high temperatures alter the natural periods to such an extent that the emission is continuous over a wide range. The writer has under way an extended study of the electrodeless discharge of certain 2 A. Kalahne, Wied. Ann., 65, 815, 1898. AUTOPSY OF A BLACK FISH TO THE EDITOR OF SCIENCE: On July 5, 1920, a large female Blackfish, Globocephalus malas, a species of whale sixteen feet long came ashore near Woods Hole, Mass., and was brought to the Fish Commission Laboratory at this place for autopsy. The task was new to all present and when a large sac capable of holding a pailful or two was seen near the posterior end of the body, it was at once recognized as probably the empty bladder. This, however, proved to be incorrect for the empty urinary bladder was found near as a hard, flesh-colored organ contracted to the size of a man's large elongated fist. The sac when more closely examined was found to be a recently delivered uterus, completely relaxed, upon the inner surface of which the site of the placenta could be plainly made out and with its open mouthed sinuses capable of receiving the tips of a little finger. This therefore was probably an unique case of death from post-partum hemorrhage, damp bed and absence of a marine accoucheur with his ergot. A few days later the history of the case was completed by the finding of the infant, a youngster about three feet in length, also cast ashore near where the body of the mother was found. There is no doubt the character of the case would certainly have been undiagnosed had there not been present at the post-mortum, an old general medical practitioner who recognized first that the body of the animal showed an almost exsanguine state, corroborated later by the condition of the relaxed uterus. WOODS HOLE, MASS., July 26, 1920 G. A. MACCALLUM QUOTATIONS THE NATIONAL BOTANIC GARDEN THE plan for the creation of a national Botanic Garden and arboretum that will be comparable with government gardens in other countries, and with public gardens in cities of the United States, should not be allowed to rest. There is force and sound argument in the proposal and no contrary argument. The present national Botanic Garden is national only in its name and in the fact that it is maintained at a slight cost to the nation. It is not national in its exhibit of plant forms. It was a pleasing little spot when the capital was a village. It carries one's thought back to when the mighty Library of Congress was housed in one small room in the Capitol. The Botanic Garden has made little growth in fifty years because it could not expand outside of its tall iron fence. Now the little space within that fence is being dedicated to monuments. The weight of opinion among government and private botanists and landscape architects is that the Mount Hamilton tract should be the site of the great new and really national Botanic Garden. It fronts on one of the main boulevards. It is already accessible by steam and electric railroads. It adjoins the vast public park which the government is building up from the bottom, the marshes and the margins of the Eastern branch. It thus fits into and becomes a part of the park system. These are among the reasons which botanists urge to bring the matter into public favor. But to them the strong reasons are that in this tract of land are high hills, steep slopes, gentle slopes, thick woods with many varieties of timber, deep ravines, meadows, marshes, brooks and rivulets, and about all kinds of soil which all kinds of American plants pick out for home. It is a great idea that the United States should have a Botanic Garden of which all Americans could say, "It is the greatest thing of its kind on earth."-Washington Evening Star. A NEW BIOLOGICAL JOURNAL DURING the past two decades the development of ecological studies in this country has been rapid. Five years ago, as a result of continued and insistent demand, the Ecological Society of America was organized and at once included in its membership botanists and zoologists of the pure biological sciences, foresters and economic entomologists of the applied sciences, and climatologists and geographers, whose work is closely connected with ecology. Beginning with the study of statics, the description of conditions as they exist, the science progressed rapidly into dynamics, the investigation of the behavior of plants and animals and the development of the communities in which they live. Now, by refined observation and precise experiment, ecology seeks to discover the fundamental causes which control the natural existence of living things. As ecology has broadened in its scope, so also has it deepened; as it has included questions of greater and more fundamental biological importance, so has it attracted investigators in larger numbers and of greater ability; as the products of ecological research have become more numerous and more scholarly, so has the necessity grown for adequate means of publication. Ecology, the official publication of the Ecological Society of America, is the latest addition to American biological periodicals. Yet it does not add to the number of scientific journals, for it is a continuation of the old and useful Plant World, which for several years has been largely ecological. At the St. Louis meeting of the affiliated scientific societies the Plant World Association most generously turned over its magazine, free from all liabilities, to the Ecological Society. But the new title, the new cover, the new volume number, the new editorial board, and above all the opening of its pages to articles on all branches of ecology, stamp it as a distinctly new periodical. Ecology begins its career under favorable circumstances. As the official organ of a growing society it is not wholly dependent on a subscription list for its financial stability. It is printed by the New Era Printing Company and managed through the Brooklyn Botanic Garden, the editorial control remaining with the society, undoubtedly fortunate arrangements. Its editorial board, headed by Major Barrington Moore, comprises fifteen men chosen from the leading ecologists of the country and repre senting a wide diversity of interests and activities. The first two numbers set a high standard and illustrate the broad scope of the science. The editor-in-chief contributes a short article on the scope of ecology; Ellsworth Huntington correlates atmospheric conditions with the prevalence of influenza and pneumonia; A. E. Douglass describes a new method of corre lating tree-growth with precipitation; C. E. Esterly describes experiments on the behavior of a copepod in relation to its diurnal migration; W. E. Praeger contributes a note on the ecology of herons; E. T. Wherry, using his new method of determining soil acidity, discusses the distribution of plants around salt marshes; and J. V. Hoffmann describes the establishment of a Douglas fir forest. In the second number E. B. Powers publishes the results of his experiments on the influence of temperature and concentration on the toxicity of salts to fishes; W. H. Burkholder discusses the effect of soil temperatures on healthy and diseased bean plants; C. C. Forsaith describes the anatomical reduction in alpine plants from the higher White Mountains; and there is presented the first part of an extensive report on the ecology of the plants and animals of Mount Marcy, New York, by Messrs. Adams, Burns, Hankinson, Moore and Taylor, comprising the committee on cooperation of the Ecological Society. From the foregoing it is evident that the first numbers contain material of interest to climatologists, marine biologists, zoologists, botanists, agronomists and foresters as well as to geographers, and even to the medical profession. Ecology is an illustrated quarterly, octavo; a volume of four numbers will contain 300 or more pages. H. A. GLEASON SPECIAL ARTICLES CHROMOSOMAL DUPLICATION AND MENDELIAN PHENOMENA IN DATURA MUTANTS THERE are 12 separate and distinct mutants of the Jimson weed (Datura Stramonium) which have recurred with more or less fre which distinguish them from the normal stock from which they arose. They are of feebler growth than normals and have a relatively high degree of pollen sterility, while pollen from normals is relatively good with less than 5 per cent. obviously imperfect grains when examined in unstained condition. The breeding behavior of the twelve is peculiar in that the mutant character is transmitted almost entirely through the female sex. Usually about one quarter or less of the offspring only from a given mutant reproduce the parental mutant type. The pollen entirely fails to transmit the mutant character, or transmits it only to a small percentage of its offspring. This is concluded from the fact that normal female plants crossed with mutant pollen produce no mutant offspring or only a small per-centage, and from the fact that the pollen of any of the 12 mutants seems to be no more potent in reproducing the mutants than pollen from normals. Another type of mutant, provisionally called "New Species" because of the difficulty or impossibility of crossing it with normals has relatively good pollen and breeds true. A study has been begun by the present authors of the relationship which exists in Datura between the cytological condition and the related phenomena of mutation and Mendelian inheritance. The cytological findings are based on counts of over 350 groups of chromosomes. We can confirm the report of others as to the presence of 12 pairs of chromosomes in the somatic cells of normal jimsons. The somatic number is accordingly twenty-four in contrast to the gametic number twelve. Chromosomal counts from the first division of pollen mother cells show that the gametic number in all the 12 mutants is 1 Blakeslee, A. F., and Avery, B. T., "Mutations in the Jimson Weed," Jour. of Heredity, X., 111120, Figs. 5-15, March, 1919. apparently 12 and 13 giving a calculated somatic number of 25 instead of the 24 found in normals. Whereas in normals all the gametes have 12 chromosomes, in our dozen mutants presumably half the gametes have 12 and half have 13 chromosomes. Apparently in the 13-chromosome gamete the extra chromosome is brought in by a duplication of one of the regular twelve. The suggestion lies near at hand that each of our 12 mutants is associated with, if not actually determined by, the duplication of a different individual chromosome to make up the calculated total of 25 characteristic of their somatic cells. If each of our dozen mutants is characterized by the presence of an additional chromosome in a definite one of the 12 chromosome sets, it should be possible by breeding tests to identify the mutant which has as its extra chromosome the one which carries the gene for any particular Mendelian character. This we apparently have been able to do for two of the twelve sets. The mutant Poinsettia (1) which appears to be caused by a duplication of one of the chromosomes carrying determiners for purple or white flower color will serve as an example. Poinsettia plants have 2 chromosomes in all the sets except in the one carrying the gene for flower pigmentation, which has three. Considering only the latter, we may have Poinsettia mutants, as regards their purple pigment, either triplex PPP, duplex PPp, simplex Ppp or nulliplex ppp. A duplex purple Poinsettia with the formula PPp should, if the chromosomes assort at random, be expected to form egg cells of the following types: 2P+p+pp+2Pp. The pollen grains should have the same constitution; but, since the Poinsettia character fails to be carried by the pollen to any significant extent, the effective male gametes are 2P+p. Combining male and female gametes in selfing we expect the following zygotes: 4PP + 4Pp + pp + 2PPP + 5PPp + 2Ppp. The zygotes with 2 chromosomes in the set are normals, the zygotes with 3 chromosomes are Poinsettia mutants. We should have therefore among the normals 8 purples to 1 white, and among the Poinsettias 9 purples to no whites. The expectation of an equal number of normals and mutants is practically never realized, probably because of differential mortality in early stages favoring the normals. A simplex purple heterozygote with the formula Ppp should have the following female gametic formula: P+2p+2Pp+ pp. Its effective male gametes should be P+2p Selfing a simplex purple heterozygote therefore should give offspring showing a ratio of purples to whites in normals of 5:4 and in the Poinsettias of 7:2. Several Poinsettia plants of these two heterozygous purple types have been selfed and found to give color ratios in their offspring in close agreement with the calculated values above. When Poinsettia mutants are made heterozygous for the other known Mendelian factors, segregation occurs in normal manner giving the customary 3:1 ratio for the characters involved, in both normals and Poinsettias. Two of the 12 mutants have each a single varietal type, which may be due to factors modifying the expression of the more typical complex. In addition two new mutant forms have arisen each of which in appearance seems to be a combination of two of the typical 12 recurrent mutants. It has not been possible as yet to count their chromosomes nor to study their breeding behavior. We have discussed the duplication of a single chromosome from only one of the 12 sets, producing mutants with 25 somatic chromosomes, with 3 chromosomes in one set and 2 chromosomes in the other 11. We have obtained in addition the duplication of a single chromosome from each of the 12 sets producing a mutant triploid for all the 12 homologous sets. The duplication may bring about a doubling of all the chromosomes, producing Gigaslike tetraploid mutants-the "New Species " type already mentioned. Such tetraploid plants have presumably 48 chromosomes in somatic cells and 24 in the gametes. From a study of the color ratios in over eight thousand offspring from tetraploid plants, it is possible to assert with some confidence that independent assortment of the chromosomes in the homologous sets of such tetraploid mutants is the rule. Selfed duplex purple heterozygotes throw 35 purples to 1 white, while the back-cross gives a ratio of 5:1. Simplex purple heterozygotes on the other hand give 3:1 ratios when selfed and 1:1 ratios when back-crossed. Evidence is at hand which indicates that we may have plants with other of the theoretically possible combinations of chromosomes than those mentioned in the present paper. The significance of the findings in Datura in relation to the peculiarities in inheritance in Gigas and other mutant types in Enothera will be pointed out later. It is hoped that it may be possible to publish in the near future a series of more detailed papers on the phenomena of chromosomal duplication in the Daturas. The present preliminary publi cation will suffice to emphasize the distinction which must be kept in mind between chromosomal mutations and mutations affecting only single genes. CARNEGIE STATION FOR ALBERT F. BLAKESLEE. EXPERIMENTAL EVOLUTION THE AMERICAN CHEMICAL SOCIETY. DIVISION OF BIOLOGICAL CHEMISTRY R. A. Gortner, chairman A. W. Dox, secretary The fat soluble A. vitamine and xerophthalmia: A. D. EMMETT and MARGUERITE STURTEVANT. The authors agree with McCollum that xerophthalmia is a disease which is due primarily to a lack of the fat-soluble A. vitamine. Experiments with rats fed on different planes of nutrition, all with the same precautions as to sanitation, eliminate the idea that xerophthalmia is primarily infectious as Bulley claims. The disease can not be cured by local treatment. It responds quickly to treatment per os with extracts containing the fat-soluble A. vitamine. It is not contagious. It is primarily a deficiency disease which in turn may bring about secondary infectious conditions. Biochemical changes in the flesh of beef animals during partial starvation: C. R. MOULTON. Fat |