ANIMAL PRODUCTION. 667 



There are no herds of beef cnttle in the interior, owing to the cold winters, 

 and the beef consumed consists almost wholly of cold-storage meat brought 

 from the outside. It is thought that a hardy beef animal for the interior can 

 be developed by making reciprocal crosses between the yak and the Galloway. 

 While it is true that some of the hybrids are not fertile, there are others that 

 are fertile, especially when the bull is crossed on the female yak. A letter 

 from V. Pi.sareff, director of the experiment station in the Government of 

 Irkutsk, Siberia, is given in which it is said that the yak is frequently 

 crossed on common cattle in Mongolia, that both the yak and his hybrid 

 offspring are exceedingly hardy, that they obtain their feed through the long 

 and extremely cold winter practically without the aid of the owners, and that 

 they are much used for beef and for milk, as well as for work animals. It is 

 suggested that an experiment of this nature be conducted at the Fairbanks 

 Station. 



At the Kodiak Station the herd has been reduced, the animals retained 

 being mostly those proved to have some milking qualities. It is said that the 

 Alaska settler needs milk quite as much as beef, and inquiries from prospec- 

 tive buyers are mostly for family cows. The destruction of the greater part 

 of the sheep flock by brown bears at Kodiak Station is reported. It is stated 

 that so long as the brown bear is protected by law there can be little en- 

 couragement for the live-stock industry. Galloway cattle at this station are 

 doing well. The cattle are maintained on feed natural to the country, along 

 with what can be grov.'n by cultivation. Experiments are being made with all 

 kinds of promising fodder crops that can be grown in this country for winter 

 feed for live stock. 



A contribution to our knowledg'e of the chemistry of coat color in animals 

 and of dominant and recessive whiteness, H. Onslow (Proc. Roy. Soc. 

 [Lojidon], Ser. li, 89 (1915), No. B 609, pp. 36-5S).— The author concludes from 

 his studies that " the existence of a tyrosinase in the skins of vertebrates is 

 inconclusive. A peroxidase can, however, be extracted from the skins of certain 

 colored rabbits and mice, which behaves like a tyrosinase toward tyrosin in the 

 presence of hydrogen peroxid. It can be precipitated from solution by satura- 

 tion with ammonium sulphate or by an excess of alcohol. The peroxidase 

 present in agouti, chocolate, and blue rabbits is indistinguishable in its reac- 

 tions from that present in black rabbits ; but no peroxidase could be extracted 

 from yellow and orange rabbits. 



" ' White melanin ' is not a pigment substance, nor is it the cause of 

 dominant whiteness, which is due to the presence of an inhibitor or antityrosi- 

 nase in the skin. Dominant whiteness in the English rabbit is due to the 

 presence of a tyi'osinase inhibitor in the skin, which destroys the activity of 

 tyrosinase; and the dominant white bellies of yellow and agouti rabbits are 

 due to the same cause. The inhibitor can be precipitated by saturation with 

 ammonium sulphate, and is destroyed by boiling or by standing for 48 hours. 

 Recessive whiteness in rabbits and mice is due to the lack of the enzym unit of 

 the pigment-producing system, for no tyrosinase or antityrosinase could be 

 extracted from their .skin.s. 



" There is not sufficient evidence to decide whether a chromogen is present or 

 not. The presence of an unoxidized chromogen might, however, serve to 

 explain the occurrence of certain colorless granular particles which are found 

 in the medullary ceils of the hairs of some white animals. These particles are 

 microscopically visible when stained, and in appearance very closely resemble 

 colored pigment granules. 



" The capacity of both white and colored skin extracts to oxidize dihydroxy- 

 phenols, but not monophenols, is more probably due to the catalyzing effect 



