ANIMAL PRODUCTION. 861 



Prepotency, E. N. Wentwobth {Jour. Hereditij, 6 {1915), No. 1, pp. 17-20). — 

 The author contends that the first essential of prepotency is homozygosis in 

 a dominant character. This is opjwsed to the general belief that prepotency is 

 a quality belonging to individuals rather than characters. He states that " as 

 a matter of fact it is highly improbable that there ever occurred the ideally 

 prepotent animal described by the breeder; that is, one which is able to 

 impress most of his characters upon his progeny in spite of the females to 

 which he is mated. . . . Prepotency is never a property of the individual, but 

 belongs to a certain few characters that are part of the hereditary makeup of 

 the individual, and their condition as to homozygosis or heterozygosis is the 

 entire determining factor. The degree by which one animal is more ' strongly 

 hved' for a character than another animal is this wide degree of purity or 

 hybridity." 



The author believes that prepotency is not entirely a property of the male 

 sex, as many breeders contend, but exists in both sexes. It is thought that 

 the linkage or coupling of separate factors in heredity explains observed pre- 

 potency and the difference between "breeders of breeders" and "breeders of 

 performers." 



Variability of cattle, J. H. W. T. Reimeks {Jahrb. Wiss. u. Prakt. Tierzucht, 

 9 {1914), pp- 1S2-162, figs. 6). — This reports a biometrieal study made of the 

 body measurements of 300 Holstein cows from 2J to 3 years old. 



The effect of lead on the germ cells of the male rabbit and fowl as indi- 

 cated by their progeny, L. J. Cole and L. J. Bachhuber {Proc. Soc. Expt. 

 Biol, and Med., 12 {1914), No. 1. pp. 24-29). — In these studies it was demon- 

 strated that the offspring produced by male rabbits which have been poisoned 

 by the injection of lead acetate into the alimentary tract have a lower 

 vitality and are distinctly smaller in average size than normal offspring of 

 unpoisoned males. Similar results were obtained with fowls. 



On the ovarian factor concerned in the recurrence of the estrous cycle, 

 F. H. A. Marshall and J. G. Runciman {Jour. Physiol., 49 {1914), No. 1-2, 

 pp. 17-22, figs. 2). — ^The authors conclude from their experiments that "the 

 occurrence of 'heat' (proestrum and estrus) in dogs does not depend upon the 

 presence of mature (or nearly mature) Graafian follicles in the ovaries. It is 

 equally evident that it is not dependent upon corpora lutea. It must be sup- 

 posed, therefore, that the ovarian factor in tlie recurrence of 'heat' resides in 

 some other ovarian element or combination of elements. The ovarian interstitial 

 cells are possibly concerned in the process, but cyclical changes in the condi- 

 tion of these cells have not so far been observed in the dog's ovaries. 



" The view which has generally been maintained that the ripening of the 

 Graafian follicles and the onset of menstruation or heat stand to one another 

 in the relation of cause to effect, must be finally abandoned. It is probable that 

 both series of changes are effects of some more deep-seated ovarian phe- 

 nomenon." 



Studies in the blood relationship of animals as displayed in the composi- 

 tion of the serum proteins.— Ill, A comparison of the sera of the hen, turkey, 

 duck, and goose with respect to their content of various proteins, W. B. 

 Thompson {Jour. Biol. Chem., 20 {1915), No. 1, pp. 1-6). — In continuation of 

 work previously noted (E. S. R., 28, p. 875; 30, p. 68), the author has deter- 

 mined the average percentage of insoluble globulin, total globulin, and totnl 

 albumin in the sera of the hen, rooster, turkey, duck, and goose. 



Studies in the blood relationship of animals as displayed in the composi- 

 tion of the serum proteins. ^IV, A comparison of the sera of the pigeon, 

 rooster, and guinea fowl with respect to their content of various proteins 



