ANIMAL PRODUCTION. 869 



(1912), 2\'o. 399, II, p. 856). — A substance which uppears to be a pyrimidin base, 

 forming a constituent of nucleic acid, was isolated from yeast, milk, brain, and 

 possibly lime juice. From 0.02 to 0.04 gm. in food prevented polyneuritis in 

 pigeons. 



The influence of meal hours upon energy elimination in man, J. Amab 

 (Compt. Rend. Acad. Sci. [Paris], 15', U912), No. 8, pp. 528-531; Jour. Physiol, 

 et Path. Gen., U (1912), No. 2, pp. 298-308; ahs, in ZentU. Expt. Med., 1 (1912), 

 No. lit, pp. 63/,, 635; Zenthl. Physiol., 26 (1912), No. 7, pp. 351, 352).— In these 

 experiments the effect on the respiratory quotient and oxygen consumption of 

 carbohydrate as compared with nitrogenous food, and of a constant amount of 

 work performed at different intervals after ingestion of food was noted. 



The author concludes that the performance of a given amount of work is 4.5 

 per cent more difficult and that the energy is available much more slowly on 

 a nitrogenous than on a carbohydrate diet. 



The influence of dry and moist air on gaseous metabolism, H. Mussch- 

 HAUSER and H. Hidding (Biochcm. Ztschr., J,2 (1912), No. 5, pp. 357-371; ahs. 

 in Jour. Chan. ^oc. [London], 102 (1912), No. 599, II, p. 8-50 ) .—Experiments 

 were made to determine the effect of humidity on gaseous metabolism, using 

 guinea pigs. 



At 5° C. there was 76.5 per cent more of carbon dioxid in dry air, and 82.8 

 per cent more in moist air, than at 21°. There was 18.7 per cent less carbon 

 dioxid in dry air, and 7.1 per cent more in moist air, at 35° than at 21°. Car- 

 bon dioxid metabolism at 21° is greater in dry than in moist air. 



The author's explanation of the observed facts is that the lower the tempera- 

 ture, the greater the degree of saturation with water vapor, and consequently 

 the less the loss of body heat. Increase of moisture diminishes carbon dioxid 

 production, while decrease of moisture has the opposite effect. At higher tem- 

 peratures, increase in moisture content up to the point of saturation is associ- 

 ated with increased body temperature, indicating increased metabolism. The 

 results in relation to size of body surface are discussed. 



ANIMAL PRODUCTION. 



The nature, origin, and maintenance of life, E. A. Shafer (Nature 

 [Londoti], 90 (1912), No. 2236, irp. 7-19; Sci. Amer. Sup., 7.', (1912), Nos. 1918, 

 pp. 221-223; 1919, pp. 226, 227; 1920, pp. 254, 255).— This is the inaugural 

 address of the president of the British Association for the Advancement of 

 Science, 1912, and discusses the fundamental principles governing the origin, 

 growth, and maintenance of animals and plants as revealed by physical, chemi- 

 cal, and biological studies. 



The process of reproduction in organisms, 0. M. Child (Biol. Bui. Mar. 

 Biol. Lab. Woods Hole, 23 (1912). No. 1, pp. 1-39).— A discussion of the repro- 

 ductive power of both somatic and germ cells. 



It is stated that the experimental data of recent years do not support the 

 germ plasm hypothesis of Weismann. The view is also expressed that our 

 theories of heredity, instead of being based solely on the phenomena of sexual 

 reproduction, must find their basis for analysis and interpretation in the 

 simpler forms of asexual and experimental reproduction. Heredity is defined 

 as the capacity of the physiologically or physically isolated part for regulation. 



The interstitial cells and the supposed internal secretion of the chicken 

 testis, Alice M. Boring (Biol. Bui. Mar. Biol. Lah. Woods Hole, 23 (1912), No. 

 3, pp. 11,1-153, fifjs. 9). — The object of this work was to find evidence of the 

 reproductive organs as a cause for the development of secondary characters. 



