ANIMAL PKODUCTION. 163 



The significance of the pathological in inheritance and selection, E. Joest 

 (Berlin. Tierarztl. Wchnschr., 27 (1911), Xo. 26, pp. .'{61-463, fig. 1).—A critical 

 review of the article noted above. 



On graft hybrids, C. C. Guthkie (Anier. Breeders Assoc. [Proc], 6 (1910), 

 pp. 356-373, figs. 10). — A review of work done in transplanting ovaries by dif- 

 ferent investigators. A bibliography is appended. 



[Experiments in hybridizing animals], W. J. Spillman et al. (Amer. 

 Breeders Assoc. [Proc], 6 (1910), pp. 131-134).— This is a report of the com- 

 mittee on work in animal hybridization now being conducted in the United 

 States, both by private individuals and institutions. A list of state experi- 

 ment stations and the nature of the breeding work at each is given. 



The fertility of the hybrids of Bos taurus and Bison americanus, E. 

 IWANOFF (Biol. Ccntm., 31 (1911), No. 1, pp. 21-24).— Oi\ a Russian estate 

 crosses were made with Bos taurus and Bison americanus. The female off- 

 spring were fertile, but the male half-breeds were sterile. Males of three- 

 quarters Bison blood were fertile. When a three-quarter Bison was crossed 

 with a one-quarter Bison the offspring produced, called a half-bred Bison 

 by the author, were fertile. 



On the question of the fertility of horse hybrids, zebroids, and hybrids 

 between the domestic horse and Equus przewalskii, E. Iwanoff (Biol. 

 Centhl., 31 (1911), No. 1, pp. 2//-28).— Offspring of both sexes produced by 

 crosses between the domesticated horse and E. przeioalskii were fertile, but 

 the male offspring of the domesticated horse and mountain zebra were infertile. 

 The results of other investigators with these hybrids, the causes of infertility, 

 and the relationship between the different species of Eqioiis are discussed. 



Bibliography of animal hybrids, F. B. Mumford (Amer. Breeders Assoc. 

 [Proc], 6 (1910), pp. 282, 28.^).— This includes hybrids among the birds and 

 mammals only, and most of these refer to domesticated species. 



[Physiology of the cell], A. B. McCallum (Rpt. Brit. Assoc. Adv. Sci., 

 1910, pp. 740-755). — This is the address of the president of the section on physi- 

 ology of the British association in 1910. 



It is pointed out that the study of the cell has been largely morphological, 

 and that the generalization drawn from these studies can give but little insight 

 into the chemical constitution or the physiological properties of the cell. Diges- 

 tion experiments on cells are also misleading. What is needed is a more definite 

 knowledge regarding the nature of osmosis, surface tension, and chemical reac- 

 tions taking place inside of the living cell. The author found that inorganic 

 salts are not diffused uniformly throughout, their localization being due to the 

 action of surface tension. Explanations are given for the belief that the energy 

 concerned in secretion, excretion, cell division, muscular contraction, and the 

 production of nervous impulses are manifestations of surface tension. 



The new force — niitokinetism, M. Hartog (Rpt. Brit. Assoc. Adv. Sci., 1910, 

 pp. 628, 629). — A discussion of the possible causes which are concerned in the 

 formation of the spindle during mitosis. The author finds that the phenomena 

 can not be accounted for by osmosis, currents, electrolytic, electrostatic, or other 

 forces unknown outside the living cell. 



Experimental zoology. II, Regeneration. Ill, Phylogeny, H. Przibram 

 (Experimentaizoologie. Leipsic and Vienna: II, Regeneration (Wiedererseur 

 gung), 1909, pp. 338, pis. 16; III, Phylogenese (ArtUldung) inklusive Hereditat, 

 1910, pp. 315, pis. 24; rev. in Biol. Centhl., 31 (1911), No. 11, pp. 346^352; 

 Nature [London], 86 (1911), No. 2164, pp. 238, 239). — These volumes comprise 

 parts 2 and 3 of a work, the first part of which has been previously noted 

 (E. S. R., 21, p. 771). Part 2 discusses in great detail the phenomena of re- 

 generation in all types of animals, from reproduction in unicellular organisms 



