ANIMAL PRODUCTION. 575 



bility of making measurements and obtaining more accurate data concerning 

 cliaracteristics of live stoclc is pointed out. 



Artificial breeding, W. R. Gilbert {Country Gent., 75 (1910), No. SOU, 

 p. 1106). — Among tlie factors pointed out as liable to induce deterioration in stock 

 from man's interference with nature's methods, because of his desire to breed 

 at any cost from animals which possess certain qualities or because of their 

 pedigree, are artificial impregnation, defects accompanying parturition, and 

 artificial selection in the attempt to produce monstrosities such as a large head 

 on the bulldog. 



Notes on heredity and evolution, W. J. Spillman (Ainer, Nat., /fJf {1910), 

 No. 528, pp. 750-762; JfO {1911), No. 529, pp. 60-64). — A review of some recent 

 investigations on mutation and Mendelian inheritance. 



The sexual functions, H. Busquet {La Fonction Sexuelle. Paris, 1910, pp. 

 XIV +359, figs. 15). — This book is a general treatise on the anatomy and 

 physiology of the reproductive organs. A bibliography of the literature is 

 appended. 



Principles of secondary sexual characters, H. Poll {Sitzbcr. Gescll. Naturf. 

 Freunde Berlin, 1909, No. 6, pp. 331-35S, figs. //). — The author describes the 

 following abnormalities which came under his observation : Drake feathering in 

 ducks, horn building in a doe, mock hermaphroditism in goats, and lateral her- 

 maphroditism in the bullfinch. Experiments are also briefly reported on cas- 

 trating drakes, castrating and transplanting ovaries and testicles in fowls, and 

 transplantation of the feathered skin of ducks. 



From the.se results, as well as those reported by other observers, the author 

 concludes that sexual differences may be either gradative or alternative. In 

 the former case the sex, as well as the secondary sexual characters, is deter- 

 mined by the environment during the development of the individual. 



Maturation, V. Gregoire {Cellule, 26 {1910), No. 2, pp. 223-422, figs. 145; 

 ahs. in Zentbl. Allg. u. Expt. Biol., 1 {1910), No. 15-16, pp. 555-558).— A compre- 

 hensive and critical discussion of the results of investigation of nuclear division 

 and the exclusion of the polar bodies in maturation of sex cells in both plants 

 and animals. The significance of each phase in the process is considered in 

 detail. 



A bibliography is appended. 



The dominance of maternal or of paternal characters in Echinoderm 

 hybrids, D. H. Tennent {Arch. Enticickl. }Iech. Organ., 29 {1910), No. 1, pp. 

 1-14, fiffs. 2). — The author's work on the hybridization of Echinoderms shows 

 that the factor determining the dominance is the variation in the alkalinity of 

 the sea water in which the embryo develops, that is, that dominance may be 

 swung either toward the paternal or maternal side by artificial means. 



Further proofs of the increase in permeability of the sea urchin's egg to 

 electrolytes at the beginning' of development, J. F. McClendon {Science, 

 n. scr.. 32 {1910), No. 818, pp. 317, 3i8).— The author recounts 3 different 

 methods of demonstrating that electrical conductivity increases as the egg 

 begins to develop after fertilization, namely, (1) decrease in electrical resistance, 

 (2) less rapid disintegration of the anode region, and (3) increased plasmolysis. 



On the dynamics of cell division. — II, Changes in permeability of devel- 

 oping eggs to electrolytes, J. F. McClendon {Amer. Jour. Physiol., 27 {1910), 

 No. 2, pp. 240-275, figs. 3). — A continuation of the work noted above on arti- 

 ficial parthenogenesis and dynamics of cell division. A repetition of Robert- 

 son's experiments leads the author to conclude that the cleavage furrow is a 

 region of increased surface tension, rather than of decreased surface tension, 

 as suggested by Robertson (E, S. R., 22, p. 272) and others. 



