(1) Ursprung der Geschlechtsunterschiede (2) Die biologischen Grundlagen der sekundren Geschlechtscharaktere (3) Sex Antagonism (4) The Nature and Origin of Secondary Sex Characters (5) Les Problmes de la Sexualité (6) Heredity and Sex

Abstract

KAMMERER has made all students of the biology of sex his debtors by taking a scholarly and critical survey of most of the recent contributions to the subject, and of the experimental work in particular. His treatise is a model of fairness and thoroughness, and must have involved a prodigious industry. He deals with the determination of sex, the theories of sex dimorphism, the results of experiments in castration, regeneration, transplantation, breeding, and environmental influence, and at very considerable length with the recent work on the internal secretions of the reproductive organs. The bibliography occupies twenty-three pages of small type ! An attempt may be made to indicate Kammerer's general conclusions. The first important step in the evolution of sexual reproduction was the specialising of germ-cells as distinguished from body-cells. The second was the differentiation of macrogametes and microgametes, which are contrasted in their assimilation capacities, amount of cytoplasm, size, and activity. The factors that condition maleness (“mikrogametismus”) or femaleness (“makrogametismus”) are ultimately assimilation differences—the thesis, it may be recalled, of “The Evolution of Sex” (1889), to which no reference is made in text or bibliography. The differentiation of sex doubtless occurred very early in phylogeny, and the determination of sex occurs correspondingly early in ontogeny. During maturation the gametes are probably in varying degrees susceptible to environmental influence, so that their predisposition to one sex or the other may be changed, but the higher the animal the less is its susceptibility. Only in plants and in the lower animals can we now succeed in experimentally changing the progamic predisposition, activating the tendency which should otherwise remain latent.

(1) Ursprung der Geschlechtsunterschiede.

By Dr. Paul Kammerer, in Fortschritte der Naturwissenschaftlichen Forschung. Herausgegeben von Prof. Emil Abderhalden. Bd. V., pp. 1240. (Berlin and Vienna, Urban and Schwarzenberg, 1912.) Price 15 marks.

(2) Die biologischen Grundlagen der sekundren Geschlechtscharaktere.

By Dr. J. Tandler Dr. S. Grosz. Pp. 169. (Berlin: Julius Springer, 1913.) Price 8 marks.

(3) Sex Antagonism.

By Walter Heape. Pp. 217. (London: Constable and Co., Ltd., 1913.) Price 7s. 6d. net.

(4) The Nature and Origin of Secondary Sex Characters.

By F. W. Ash. Trans. North Staffordshire Field Club. xlvii. (1913), pp. 7993.

(5) Les Problmes de la Sexualit.

By Prof. Maurice Caullery. Pp. 332. (Paris: Ernest Flammarion, 1913.) Price 3.50 francs.

(6) Heredity and Sex.

By Prof. T. H. Morgan. Pp. ix + 282. (New York: Columbia University Press; London: Oxford University Press, 1913.) Price 7s. 6d. net.