268 EXPERIMENT STATION RECORD. [Vol.38 



on so-called deficiency diseases, which seems to show that beri-beri and xeroph- 

 thalmia arc due to the absence of a specific unidentified factor, but that pellagra 

 and scurvy are not due to such a factor. There is doubt whether scurvy is a 

 distinct entity, and the theory of infection in pellagra is still a possibility. 



ANIMAL PRODUCTION. 



The nutrition of farm animals, H. P. Aemsby {New York: The MacmiUan 

 Co., 1911, pp. XVIll-\-lli.i, fujfi. -}5). — This work does not claim to be another 

 edition of facts in feeding, but treats as far as possible with our present scope of 

 knowledge of the fundamental laws governing the nutrition of farm animals. 

 The animal body is treated as a transformer of energy partly into motion 

 and incidentally into a reserve material which can be utilized as humau food. 

 It is the latter phase which this volume presents. 



The Avork is divided into four parts. The first deals with materials of 

 nutrition, the food compounds of plants and animals and the composition of 

 cells, tissues, and organs. Part 2 deals with the physiology of nutrition or the 

 methods of transference and building in the animal organism. Part 3 treats of 

 the needs of animals and the amounts of matter and energy necessary in pro- 

 ducing the materials or work for which they are kept. The fourth part con- 

 siders the feed supply, values, and rationing. An appendix exhibits tables of 

 the maintenance, fattening, milk and work production requirements of different 

 animals, and the food values of various feeding stuffs. 



The work deals with the natural laws governing the nutrition of farm animals 

 rather than with the broader field of animal husbandry. It is, therefore, in- 

 tended for the student with some knowledge of chemistry and physics and not 

 for the general farmer. 



The direct and indirect effects of X-rays on the thymus gland and re- 

 productive organs of white rats, Evelyn E. Hewer {Jour. Physiol., 50 {1916), 

 No. 7, pp. 43S-458, fig. 1). — A study was made of the direct effects of X-rays 

 on the thymus and male and female gonads of white rats, and of the indirect 

 effects of the rays on nonirradiated organs. 



Irradiation of the thymus only causes slight degeneration of the male gonads 

 and delay of sexual maturity, but no alteration in the female. Irradiation of 

 the whole animal when very young with a very small dose hastens sexual 

 development in the male. Irradiation causes a degeneration of the testes. The 

 more immature the testes and sperm cells the more easily they are affected by 

 X-rays. Irradiation of the male and female gonads has a marked indirect effect 

 on other organs, especially on the thymus. Primordial and young ova are more 

 resistant to the action of X-rays than older follicles. The corpora lutea become 

 abnormally vascular, but appear otherwise unchanged. Hypertrophy of the 

 interstitial gland is constant, and persists even after apparent regeneration of 

 the ovary. 



A list of 19 references is included. 



The numerical results of diverse systems of breeding, with respect to two 

 pairs of characters, linked or independent, with special relation to the 

 effects of linkage, H. S. Jennings {Genetics, 2 {1911), No. 2, pp. 97-154).— In 

 this continuation of the study of methods of measuring results of systems 

 of breeding (E. S. R., 34, p. 764), the author gives formulas for finding in later 

 generations the results of continued breeding by a given system when two 

 pairs of characters, linked or independent, are considered. The systems of 

 breeding considered are (1) random mating, (2) selection with respect to a 

 given single character, (3) assortative mating with respect to a single character, 

 and (4) self-fertilization. In each system two cases are dealt with, that in 



