ANIMAL PRODUCTION. 869 



Broodlness, which was more frequent auioiig Plymouth Rocks than among 

 Leghorns, was most pronounced in the best layers. It was found that IG 

 days after mating the hens still laid fertile eggs. When mating was repeated 

 after a period of more than 16 days, the first fertile egg was generally laid 3 

 days and sometimes 4 days later. It was found iw.ssible to influence the color 

 of the eggshell by pairing a cocls of a breed which has yellow or brown eggs 

 with a hen of another breed that lays white eggs, or vice versa, the breed of 

 the hen alone being responsible for the color of the eggshell. 



Winter egg production, Helen D. Whitaker ( Washington Sta. Popular Bui. 

 76 (1914), pp. 15). — This gives general information on the selection, housing, 

 care, feeding, and management of poultry for winter egg production. 



How to care for the little chick, E. L. Andrews (West Virginia Sta. Circ. 

 11 (1914), pp. -'()■ — General information on the care of young chicks. 



Experimental studies of hybridization among ducks and pheasants, J. C. 

 Phillips (Jour. Expt. Zool., 18 {1915), No. 1, pp. 69-143, figs. 9).— This article 

 reports hybridization experiments in which a study was made of the plumage 

 characters in wild species of birds, this being almost wholly an investigation 

 into the inheritance of male secondary sex-characters. 



It was found that characters often apparently clear-cut and antagonistic do 

 not segregate clearly. " There is some evidence that in closely related geo- 

 graphical races there is a nearer approach to orthodox Mendelism, but this is 

 never reached, even in back crosses, except occasionally in isolated characters 

 or in the more undifferentiated plumages of the female sex. In species with 

 unrelated character complexes there are only slight tendencies to a greater 

 variation In F2 than in Fi, as is shown in the pintail X mallard cross, or the 

 Australian X mallard cross. Such variation, comparable to that seen in size 

 characters, may be explained as the manifestation of factor c^mplexes, out- 

 wardly expressed in plumage characters, but not by any means necessarily 

 specific units for these epidermal structures alone. . . . 



" Sex-linked inheritance is probably a feature of domestic races in birds. 

 In wild species thus far examined there is no clear evidence of unequal trans- 

 mission by the sexes. Both sexes can carry the characters of the opposite sex 

 through several generations without an additional 'dose' of the character 

 in question." 



Hints on goose culture, Helen D. Whitaker (Washington Sta. Popular Bui. 

 83 (1915), pp. .}). — General information on the feeding, care, and management 

 of geese. 



Some factors affecting the weight, composition, and hatchability of hen 

 eggs, H. Atwood (West Virginia Sta. Circ. 9 (1914), PP- 4)- — ^This is a popular 

 account of material previously reported (E. S. R., 31, p. 270). 



A study of the relation of the chemical composition of hens' eggs to the 

 vitality of the young chick, L. J. Cross (Thesis, Cornell Univ., 1912, pp. 16). — 

 In this work the author attempted to determine the relation of the vitality of 

 the chick to the chemical composition of the egg, and to control the composition 

 of the egg. The results are summarized as follows: 



" The work on the coloring of the parts of the eggs by feeding dyes to the 

 hen indicates that the fat found in the albumin region of the incubated egg is 

 derived not wholly from the yolk, but from another source, the albumin itself. 

 The percentage of fat in the yolk of the weak chick is in some cases less and 

 sometimes more than in the yolk of the strong chick. The weak chick is equally 

 as rich in phosphorus as the strong chick. The phosphorus content of the egg 

 varies but little. There is no increase in the phosphorus content of the egg 



94863°— No. 9—15 6 



