670 EXPERIMENT STATION RECORD. [Vol.43 



siders it probable that the peculiar ratios observed by Dunn (E. S. R., 42, 

 p. 702) wore chance deviations from ordinary no-linkage ratios, but points out 

 that a lethal factor might be invoked to explain the results. 



Experiments on sex determination, S. M. Copeman (I'roc. Zool. Soc. Lon- 

 don, 1919, III-IV, pp. Jt3S-JtS5) .—To test the theory that in mammals the 

 gonads on one side of the body give rise to male-producing gametes and those 

 on the other side to female-producing gametes, the author made various matings 

 of semicastrated and semispayed rabbits. The operations were without influence 

 on the sex ratios among the progeny. The experimental data are not reported. 



Studies on the cells of cattle with special reference to spermatogenesis, 

 oogonia, and sex determination, .1. E. Wodsldai^ek (Biol. Bui. Mar. Biol. Lab. 

 Woods Hole, S8 {1920), No. 5, pp. 290-316, pis. 5, fig. i).— This is a contribution 

 from the Idaho Experiment Station. 



The author's counts gave quite uniformly 37 chromosomes in the sperma- 

 togonia of adult bulls and in the somatic tissues of male fetuses. The unpaired 

 (sex) chromosome is larger than the ordinary chromosomes and passes undi- 

 vided to one pole at the first spermatocyte (reduction) division. Measurements 

 of mature spermatozoa indicated a rather definite dimorphism in head length, the 

 larger type presumably containing the sex chromosome. Two sex chromosomes 

 were observed in the oogonia of female embryos. 



The spermatogenesis of domestic mammals, I, II, K. Masui (Jour. Col. 

 Agr., Imp. Univ. Tokyo, 3 (1919), No. 6, pp. 351-Jt03, pis. 6, figs. 3).— Two papers 

 are presented dealing, respectively, with the horse and the bull. Besides the 

 chromosome relationships, the mitochondria, idiosomes, and other cytoplasmic 

 inclusions are described. The materials from which the preparations were 

 made were secured in Japan. 



I. The spermatogenesis of the horse (pp. 357-373). — The somatic number of 

 chromosomes is found to be 37. The odd chromosome appears as a chromosome 

 nucleolus in resting and growth stages, and passes undivided to one pole at the 

 first spermatocyte (reduction) division. 



II. The spermatogenesis of cattle (pp. 377-398). — The number of chromosomes 

 counted in spermatogonia! divisions was 33. The odd chromosome stained as a 

 chromosome nucleolus, and could be traced throughout the growth stage. It 

 remained undivided at the first spermatocyte (reduction) division. 



" In the testes of embryos and quite young animals the spermatogonia are 

 divided by amitosis, and in such young individuals amitosis occurs more fre- 

 quently than mitosis. Judging from their nuclear organizations and other 

 structures, it is evident that the cells produced by amitosis are degenerating, 

 being used as nutritive materials by the germ cells." 



On cellulose digestion in vitro for the purpose of estimating the digesti- 

 bility of feeds containing cellulose, P. Waentig and W. Gierisch (Hoppe- 

 Seyler's Ztschr. Physiol. Chem., 101 (1919), No. ^-5, pp. 213-22^).— The authors 

 have studied the ability of the microflora of fluid from the cecum, colon, and 

 feces of the horse to digest cellulose by comparing the digestive action in vitro 

 of fresh untreated fluid with that of sterile fluid. Neither untreated pine- 

 wood meal nor hydrolyzed pine needles was digested by the bacteria, nor to 

 any extent by experimental animals (species not stated). On the other hand 

 sulphite paper pulp, rye straw meal, and rye straw pulp were digested in vary- 

 ing degrees in vitro and by animals. Unless there are marked differences be- 

 tween feeding stuffs in the extent to which their crude fiber is utilized by ani- 

 mals, the in vitro method does not seem to grade them accurately. 



Kudzu feeding experiments, A. F. Kidder (Louisiana Stas. Rpt. 1919, pp. 

 15, 16). — Three Hereford cows were maintained on an acre plat of kudzu for 



