272 EXPERIMENT STATION BECORD. [Vol.35 



The results of these experiments showed a higher energy consumption for 

 older steers than those secured by Dahm (E. S. R., 25, p. 674), but were in 

 close agreement with the Armsby calorimeter results (E. S. R., 15, p. 799). 

 It was apparent that the maintenance requirements in the various ages of 

 cattle were in proportion to the body surface. 



Nondisjunction as proof of the chromosome theory of heredity, C. B. 

 Bbidges {Genetics, 1 (1916), Nos. 1, pp. 1-52, pi. 1, figs. 8; 2, pp. 107-163, pi. 1, 

 fig. 1 ) . — In this paper experimental proof is offered that " particular chromo- 

 somes, the X chromosomes, are the differentiators of sex ; the X chromosome 

 constitution of an individual is the cause of the development by that individual 

 of a particular sex, and is not the result of sex already determined by some 

 other agent. The sex is not determined in the egg or the sperm as such, but 

 is determined at the moment of fertilization ; for the X sperm of the male 

 gives rise to a female when it fertilizes an egg containing an X, but to a 

 male if it fertilizes an egg containing a Y or no sex chromosome at all. Like- 

 wise the Y sperm of a male gives rise to a female when fertilizing an XX egg 

 and to a male when fertilizing an X egg. These facts in connection with 

 the fact that an X egg of a female produces a male if fertilized by an X 

 sperm prove that the segregation of the X chromosomes is the segregation of 

 the sex differentiators. The presence of two X chromosomes determines that 

 an individual shall be a female, the presence of one X that the individual 

 shall be a male. The origin of these chromosomes whether maternal or 

 paternal is without significance in the production of sex. 



" The Y chromosome is without effect upon the sex or the characters of the 

 individual, for males may have one Y, two Y's, or may lack Y entirely 

 (males lacking Y are sterile) ; and females may have one or two super- 

 numerary Y's with no change in appearance in any case." 



A bibliography of references is appended. 



A sex-limited color in Ayrshire cattle, E. N. Wentwobth ( XJ. S. Dept. Agr., 

 Jour. Agr. Research, 6 (1916), No. 4, pp. 141-1^7). — It is stated that a case 

 which seems to fall under the sex-limited group is found in the inheritance of 

 black and white as alternative to red and white in Ayrshire cattle. If the factor 

 for the black and white color is represented by B, the hereditary constitu- 

 tions are as follows : BB is always black and white ; bb is always red and 

 white; and Bb is always black and white in the male and red and white in the 

 female. 



In breeding experiments at the Kansas Experiment Station all of the nine 

 possible matings were discovered. From the data obtained it appears that the 

 black and white color of Ayrshire cattle behaves in an ordinary sex-limited 

 manner similar to the horns in sheep as discussed by Wood " and the rudimen- 

 tary mammae in swine as reported by the author (E. S. R., 27, p. 769). 



It is concluded that black and white color is a simple allelomorph of red and 

 white color in Ayrshire cattle. In the male the black and white character is 

 dominant and in the female the red and white character is dominant. Males 

 heterozygous for the two characters are black and white, while females hetero- 

 zygous for the two characters are red and white. 



Sheep raising in Wisconsin, F. Kleinheinz (Wisconsin Sta. Bui. 263 (1916), 

 pp. 19, figs. 11 ) . — This bulletin deals with the opportunities for successful sheep 

 raising in Wisconsin and the methods of care, feeding, and management. 



Fish meal as food for pigs, C. Crowthee (Jour. Bd. Agr. [Londoyi]. 23 

 (1916), No. 1, pp. 21-33). — Pigs fed fish meal in addition to a basal ration of 

 bran and middlings made 1.35 lbs. greater gains per pig weekly than those fed 



•Jour. Agr. Scl., 1 (1905), No. 3, pp. 364, 365. 



