(ibid., March, 1914) to account for the action of a magnetic field (Zeeman) and an electric field (Stark, Lo Surdo) on the emission of light (see supra). The theory is a mixture of mechanics and non-mechanics, since the motion of the electrons in their equilibrium paths is determined by mechanical laws, while the passage from one path to another is entirely undetermined except as to the supposed emission of light according to the quantum theory. Opinions as to the ultimate value and truth of Bohr's hypothesis differ greatly, and it has already called forth an extensive literature. At first sight it looks merely like an arbitrary model giving a series line emission by hypothesis. Nicholson (ibid., July, 1914) considers that it is not entirely self-consistent, and that it can so far do little more than account for the Balm the frequency of the resulting y ray, series lines of the atom. Bohr has it follows that 180,000 volts applied still further extended his theory to an X-ray tube should give X-rays of the same wave-length and penetration as the most penetrating y rays. With the new Coolidge tube it will probably be possible to do this. The velocity of the ẞ rays from radium B or radium C is considerably greater than this. Rutherford and Robinson have also examined (by magnetic separation) the B rays given off by lead when excited by the y rays from radium emanation, and find that about half of the distinct groups of B rays are almost identical, as regards velocity, with groups in the 8 ray emission from radium B; which is further evidence of the close similarity between radium B and lead, though their atomic weights differ by seven units. For other metals the excited rays were very different. This and other evidence indicates strongly that the final product in the uraniumradium family is lead, but the evi-er's series of hydrogen. Nevertheless dence that it is also lead in the case of the thorium family is so far very slight (Holmes, Nature, April 2, 1914; Lawson, ibid., July 2, 1914). In Le Radium (Jan., 1914) Kalowrat has published a very complete table of radioactive data and constants. Atomic Structure.-Interest in this field has centered around Rutherford's hypothesis of a nuclear atom, suggested in 1911 to account for the nature of the scattering of a particles in passing through gases. According to this hypothesis atoms consist of a relatively very small nucleus (estimated diameter less than 2 x 10-13 cm.) surrounded by relatively distant electrons. Late in 1913 the idea was put in more definite theoretical form by Bohr (Philos. Mag., xxvi), who supposed the electrons to have certain definite paths of rotation around the nucleus, this rotation not being accompanied by any emission of light. Emission only occurred when an electron, due to some external disturbance, passed from one equilibrium path to another, and the various paths were so taken that the difference in energy content of the electron in any two paths, divided by the quantum constant h, gives the frequency of one of the known spectral there are many striking ways, both qualitative and quantitative, in which it fits the facts. The resultant positive charge of the nucleus is now very generally supposed to be numerically equal to the atomic number of the element as above defined; this suggestion was originally due to Van den Broek (Phys. Zeit., xiv, 32), and Bohr (Philos. Mag., Dec., 1913) has supposed that the chief line of Moseley's X-ray spectrum could be accounted for by a ring of four electrons rotating around a nucleus thus charged. But Nicholson (ibid., March, 1914) concludes that it is so far impossible to find any satisfactory connection between Bohr's theory and Moseley's X-ray spectra, though the general idea that the properties of an atom are determined by its nucleus charge, or some simple function of it, rather than by its atomic weight, is borne out by many lines of reasoning (see "Radioactivity," supra). A very interesting summary of much of this work is given by Rutherford in the Philosophical Magazine for March, 1914; also in a later discussion of the subject by a number of authorities, separately printed with the Proceedings of the London Physical Society, June, 1914. XXV. THE BIOLOGICAL SCIENCES ORGANIC EVOLUTION W. L. TOWER General Survey of Activities.—As in the past ten years, the chief activities in investigation center around the phenomena of heredity, and with increasing intensity about the behavior in inheritance which we have come to know as Mendelian. Within the year 1914, however, no new developments in this field that are striking have appeared, but rather the publications as far as they have come to us indicate much in the adding of data, and in strengthening the conceptions already established, rather than extending them. In the field of the special hypotheses of evolution no special change in the situation has taken place, and on the whole the literature of the year is scanty and inclined to be the pleading of the advocate for the special conception. One sees, however, an increasing use of the newer aspects, especially the developments in heredity, the pure-line conception, and the rôle of "mutation," in the practical operations, and investigations in applied portions of biology, agriculture, eugenics, and medicine. In the application of these new genetic principles to the problems of improvement of plants and animals of economic value, very pleasing progress is being shown at nearly all the establishments devoted to the progress of agricultural science in both America and Europe; in the latter especially, some of the best pure investigation is produced in agricultural institutions, especially in Germany and Austria. In the eugenic field the most striking aspect is the willingness to accept as true data that are of doubtful validity or even obviously not of critical character, and the furor to legislate upon any and all aspects of the problems of human society, regardless of the soundness of the principle upon which the legislation is based, and always with the naïve assumption that the human race in constitution, and society in organization and behavior, can be rapidly and permanently altered by legislative edict from its present to what is assumed to be an improved condition. Through it runs an oppressive morbidity in relation to sex and sex questions, no end of misconception of the biological meaning of sex and the rôle of sex in human society, and a disregard of the fact that among the earth's human tribes many codes of ethics regarding these intimate personal relations have been developed, each good for the possessor thereof; who among us is wise enough to decide which is the better? In America it seems as if the code of the New England Puritans is taken on purely à priori ground as the sole true standard. The eugenic literature is amusing if not instructive and the dross very far outweighs the really valuable content. It is of interest to note the establishment of a new Institut für Vererbungsforschung in Berlin under the directorship of Prof. Edward Baur for the experimental study of heredity in plants and animals. General Evolution Hypotheses.-The conceptions known as neo-Lamarckianism, neo-Darwinism, and orthenogenesis, have received no addition to their content or in confirmation during the year. Minor papers, mainly of an argumentative nature, appear sporadically, adding little or nothing to the already stupendous literature upon these hypotheses. The mutation hypothesis continues to be a topic of active investigation and discussion. During the year 1914 the chief activities have been those of Davis and Gates, who have continued their attempts to determine the nature of Oenothera Lamarckiana but without conclusive results. DeVries has presented (Bot. Gaz.) an excellent account of the taxonomy of his material, which, as far as taxonomic study is able, establishes the fact of the existence of this species in its present form for at least a hundred years. However, the belief seems to be increasing that this plant, showing in such striking manner the mutation behavior, is of hybrid origin. The attempts of Davis to create the plant anew through hybridization would have little significance unless the new creation showed the mutating behavior, and this aspect of the problem seems to be largely lost sight of. an tion from without, we must begin seriously to consider whether the course of evolution can at all reasonably be represented as an unpacking of original complex which contained within itself the whole range of diversity which living things present. I do not suggest that we should come to a judgment as to what is or is not probable But as we have in these respects. got to recognize that there has been an evolution, that somehow or other the forms, we may as well see whether we forms of life have arisen from fewer are limited to the old view that evolutionary progress is from the simple to the complex, and whether after all it is conceivable that the process was the other way. The defect of Bateson's conception lies in the utilization of data derived enProbably the most interesting con- tirely from the investigations of Mentribution, and certainly one that has delian behavior in inheritance, which aroused and will continue to arouse are apparently only a portion of the abundant discussion, is found in the phenomena that are concerned in evopresidential address of Prof. William lutionary processes, even though not Bateson, at the meeting of the British so intensively and expensively invesAssociation for the Advancement of tigated at present. If perchance it Science at Melbourne. Numerous par- should prove to be true that this contisan reviews have unfairly and in ception of Bateson's is correct, it is misleading fashion characterized his in effect the reëstablishment of the "theory" as "topsy-turvy evolution" ancient doctrine of causative creation, and "special-creation anew" without and evolution simply the unfolding presenting fairly Bateson's position, and release of potentialities implantand give the reader the impression ed in living materials at the beginthat it was advanced as a comprehensive theory of evolution, which is not true. Bateson, after reviewing the developments in the field of Mendelian inheritance, facts that are experimental verifications of behavior of organic characteristics in inheritance, simply offers certain suggestions for consideration, which are logical suggestions for further thought and investigation. After discussion of the recognized fact that in many instances evolutionary change takes place first by a sudden rather large departure, and that subsequently intergrades between this departure and the parent arise through the "fragmentation" of the newer type, he makes his position very clear in the following sentences: In spite of seeming perversity, therefore, we have to admit that there is no evolutionary change which in the present state of our knowledge we can positively declare to be not due to loss of characteristics. If then we have to dispose, as seems likely, with any addi ning, regardless of the effective cause of that momentous event in this planet's history. It does not seem probable that many will become devotees of this conception, nor that there is any likelihood that it will be erected into another hypothesis of organic evolution. It seems merely the interesting logical deduction into which Bateson has been driven by a too narrow and partisan outlook and interest upon phenomena comprising only a small portion of the mass of activities comprised within the different aspects of organic evolution. Evolution of Species.-Among the discussions of the year dealing with the problem of species, which are mainly interpretative of the possible origin, may be mentioned a paper by O. F. Cook, "The Existence of Species" (Jour. Her.), in which he discusses and extends his conception of the polyphyletic origin; in the same journal, C. C. Young gives an interesting account of the origin of the Karakul sheep, and L. Trabut contributes an interest-results found by Castle are due to the ing paper on the origin of cultivated oats, showing something of the ancestry, the action of environment and of culture, with the possible rôle of mutation in the rise of varieties. A. C. Chandler (Am. Nat.) presents the results of his studies of the effects of the extent of distribution, and these findings are interpreted as being due to time, isolation, induced changes produced through the action of extrinsic agents, and intrinsic changes due to the changes in habit and mode of life. The plausibilities are interesting, if not convincing. J. H. Gerould in the same journal, under the title "Species Building by Hybridization and Mutation," shows how the results of his studies in the crossing of species of Colias and their polymorphism apply in the interpretation of other somewhat similar examples among Lepidoptera. isolation of pure lines and not to the action of selection. In that two different stocks of animals were used, it is not improbable that both Castle and the Hagedoorns' data may be correct as far as their experimental findings are concerned; to be conclusive the latter investigators should test their views upon Castle's materials and vice versa. Variation and Mutation.-The publications in this department, although fairly numerous during the year, are on the whole additions of more data to the present status of knowledge rather than extensions of principles, and have to do largely with the description and analysis of the methods of origin of larger variations. From the statistical investigation of the variation problem nothing of note has been accomplished during the year. Especially interesting is the work of T. J. Stomps (Am. Nat.), giving the results of his breeding experiments with European Oenothera biennis, from which he has secured several mutants, a dwarf form, a gigas-like form, the form sulfurea and others, the whole array in some respects simulating the mutations found by DeVries in Oenothera Lamarckiana. The rise of the gigas-like form is especially interesting and may suggest to us that in both biennis and Lamarckiana, the mutation process has much in common. R. Gates has continued his investigations of the Oenotherae (Zeitschr. für indk. Abst. und Verer Adaptation. This topic, long a favorite with students of evolution, seems to be losing favor, and aside from the usual annual crop of "cases" of mimicry described by the English entomologists and attributed to the action of selection, little is presented in the publications of the year save a paper by J. F. Abbott, in volume I of the Washington University Studies, who concludes from a study of mimicry in the genus Liminetis that there is no evidence that selection has been operative in the series that he studied. Selection. This subject likewise in the literature of the year makes lit-bungslehre) and has attempted to tle advance and receives little in the way of added data. Most noteworthy is the contribution of E. M. East and H. K. Hayes (Am. Nat.), "A Genetic Analysis of the Changes Produced by Selection in Experiments With Tobacco." The authors after an extensive series of experiments show the practical value of the pure-line method to the breeder and agriculturist, and the rôle that selection may play in the purification of pure lines. A. L. and A. C. Hagedoorn (Zeitschr. für indk. Abst. und Vererbungslehre, xi) give an extensive criticism of Castle's work with hooded rats, in which he maintained that positive effects of selection were obtained. The authors, upon the basis of experiments of their own and Castle's data, maintain that the show that hybridization and mutation Among the invertebrate forms, W. Bowater (Jour. Gen.) gives his results from the examination of 211 species of Lepidoptera in which melanism is found, and finds that it is usually a Mendelian dominant but is sometimes recessive. R. K. Nabours (ibid.) gives results showing the operation of Mendelian behavior in the color patterns of the grouse locusts. Africa) describes the rise of the Bus-tained from the stud books, from tin Black Pritas breed of poultry, and which it seems that the hereditary reC. W. Mitchell and J. H. Powers lations of black and brown coat color (Jour. Exper. Zoöl.) have given in are the same as in other mammals detail their results in experiments with and that there are two types of yelthe rotifer Asplanchna, showing the low. Practical rules for color breedtransmission through the sexual as ing in dogs are also given. W. E. well as through the parthenogenic Castle (Am. Nat.) describes new vagenerations of the experimentally pro- riations in the coat color of rats and duced hump form. I. B. Sollas (Jour. guinea pigs and their relations to the Gen.) gives further results of his stud- problems of color inheritance. R. H. ies of the dwarf race of guinea pigs. Thomas (Jour. Gen.) gives his inHeredity. This literature is by far complete results in the inheritance of the largest in the field of organic evo- secondary sexual characters in pheaslution of the year, many excellent ants, apparently showing that the pieces of work being recorded, cov- inheritance is due to segregating ering a wide array of plants and ani- gametic factors. mals, but with no essential extension or change in the general principles. G. N. Collins (Jour. Her.) discusses in clear manner the nature of the Mendelian units and argues for the existence of complexity in the factors, while O. F. Cook in the same journal takes a rather different view, holding to his position that there are much blending and mixing of characters from polyphyletic sources, assuring us that "the assumption that characters are pre-existent in the protoplasm of the germ cells as discrete particles or as independent units is not justified by observation or logical necessity," and that characters are to be thought of as lines of descent instead of discrete particles. E. Fischer (Anth. und Eth. Studien am Rehobother Bastardvolk im Deut. Süd-west Africa, Jena) gives many interesting data of the crossing of human races, finding no racial prepotency but rather the apparently uniform action of Mendel's law in many characters. Along the same line are cases cited by P. Poponoe (Jour. Her.) of the crossing of Polynesian and German stock. M. M. Boyd (Jour. Her.) and C. Goodnight (ibid.) give data on the crossing of the bison and cattle, and the latter writer expresses it as his experience that the F, hybrid is greater in weight, eats less, gives better meat and does not get tough, and that the animal is docile and can do without water longer than cattle, making it a valuable meat-producing animal in these respects. W. Haynes (ibid.) gives results of inbreeding in dogs, and C. C. Little (ibid.) presents the analysis of inheritance in dogs as ob In plants, R. P. Gregory (Proc. Roy. Soc. Lond.) gives interesting data of the rise and composition of tetraploid plants in Primula sinensis; G. H. Shull (Deut. Bot. Gesell.) describes the behavior of leaf color in Melandriom album and M. rubrum, which is Mendelian, and (Zeitschr. für Abst. und Vererbungslehre) describes the action of duplicate genes in the production of capsule form in Bursa bursapastoris. Here capsule form is produced by either one of two independent Mendelian determiners, and when both are absent the form heegeri appears. There is also an interesting discussion of the relations and significance of plural and duplicate genes, which, however, is valuable only as a working hypothesis. W. E. Castle (Jour. Gen.) describes an apple chimera, between Golden Russet and Boston Stripe, apparently an ordinary case of a chimera, arising from a graft hybrid. O. F. Cook (ibid.) describes the inequality in the sex ratios of hemp, showing the greater mortality in the male plants, which is suggested to be due to some sex-limited environmental character, and that it is an advantage to the female for the males to die; he regards the case of one of "reversed effects of selection." |