DAIRY FAEMING DAIRYING. 871 



The author discredits the theory that strength or endurance goes with the 

 colors. The factors, or determiners, which control the transmission of color 

 are independent of all other qualities. The colors are unit characters and they 

 behave as simple Mendelian colors. 



It is stated that a fundamental characteristic of the chemical precursors of 

 the melanins, the chemical compounds causing the coloring of the hair-coat, is 

 their power to take up under different conditions different amounts of oxygen ; 

 small amounts of oxygen producing the lighter shades of pigmentation, while 

 larger amounts cause the darker shades until the black is reached. The factor 

 which determines the extent of oxygen resides in the germ cell. 



The possibility of so breeding horses as to secure strains of chestnut, bay, 

 black, and gray is discussed. 



The origin of domestic fowl, C. B. Davenport {Jour. Heredity, 5 {J914), 

 No. 7, pp. 313-315, figs. 4). — In this paper the author attributes the origin of 

 the domestic fowl to two distinct species, one the Jungle fowl, which is still 

 found wild, and the other the unknown ancestor of the Aseel or Malay fowl. 

 These two species are describetl and their introduction in the evolution of the 

 domestic breeds of fowl explained. 



Egg-laying- competitions, 1913-14, D. F. Laurie (Dept. Agr. So. Aust., 

 Egg-Laying Competitions 1913-1^, pp. 32). — In connection with these egg-laying 

 competitions it was noted that of 125 pens of White Leghorns observed, eggs 

 with tinted shell were collected from 71. It is believed that this is a character 

 common to all birds, but subject to the phenomenon of dilution or marking. 

 The largest number of pens showed tinted eggs during the months of June, 

 July, August, and September. 



With regard to the relationship between the characters which stand for 

 " broodiness " and those for " color of shell," it was noted that of the 125 pens 

 of White Leghorns, 51 pens were recorded for both " tinted eggs " and " broody 

 birds," while 74 pens were recorded as showing only one character. 



DAIRY FARMING— DAIRYING. 



Comparison of one- and two-day test (Guernsey Breeders' Jour., n. ser., 

 4 {1913), No. 3, pp. 13, 14)- — Results obtained by the American Guernsey Cattle 

 Club in a study of the advanced registry work the basis of a monthly one-day 

 or two-day test are summarized as follows: 



Of 41 cows selected at random from 38 herds, 16 gave during the year an 

 average of 3.23 lbs. more milk fat on the one-day test (using first day) thaa 

 on the two-day test, while the remaining 25 cows, gave an average of 5.1 lbs. 

 less on the one-day than on the two-day test. Seven cows varied less than 

 1 lb. of milk fat in a year, five less than two, seven less than three, four less 

 than four, five less than five, eleven less than between five and ten, and two 

 less than 10 lbs. The least amount of variation in the 41 cows was 0.12 lbs., 

 and the two largest were 13.63 and 16.35 lbs. milk fat. 



The records of 250 cows were then worked out, and of these, 114 cows gave 

 £^27.02 lbs. moi-e milk fat on a one- than a two-day test, while 136 cows gave 

 581.01 lbs. less. 



Comparison of one- and two-day tests. — The trustworthiness of estimates 

 of the richness in butter fat of a cow's production for a year, made by the 

 method of the Guernsey Cattle Club from one one-day test per month, 

 E. L. Thorndike {Guernsey Breeders' Jour., n. ser., 4 {1913), No. 3, pp. 29- 

 32). — From a study of the above records and the probable "error of the 

 neglect of the relation of the daily percentages of butter fat to the daily amounts 

 70903°— 14 6 



