CAROTIN, THE PRINCIPAL YELLOW PIGMENT OF MILK FAT. 331 



ticated cattle, an elimination or utilization of the pigmented fat is 

 impossible and fat colored with the pigment in a more or less modified 

 condition is thus stored up. 



There is abundant proof in this literature aside from the above 

 speculations that animals are able to lay up fat soluble dyes in the 

 organism and even eliminate them in the milk. Only recently Mendel 

 and Daniels 1 have shown that Sudan III and other fat soluble dyes 

 may be deposited in the organism in adipose tissue and bone marrow 

 when introduced into the organism either dissolved in fat or when 

 fed alone. When fed with fat or when fat was present in the alimen- 

 tary tract the dyes entered the organism through the lymphatics in 

 solution in fat, but when fat was absent, through the portal circulation 

 dissolved in bile in which they are nearly all soluble. In the latter 

 case the pigments did not pass beyond the liver unless fat was present 

 to transport them, in which case only they were subsequently found 

 in the blood. When fat stained food was fed to small animals (cats, 

 rats, guinea pigs, etc.) in lactation, and in one case with a goat, the 

 dye appeared in the milk shortly after the first feeding of the dye. 

 The same authors feeding fifteen grams of Sudan III to a Holstein 

 cow for three successive days were unable to detect the dye in the milk. 

 The authors also made the interesting observation that stained fat 

 does not traverse the placental barrier; the blood and foetus and 

 fat of the young born of Sudan-stained female cats and rats were free 

 from the dye. 



Gogitidse 2 fed hog fat (100 grams per day) colored with Sudan 

 III to a bitch and after two days found the dye in the milk. The 

 body fat did not show this coloration so soon and then not so clearly, 

 in fact only after long continued feeding of the stained fat. 



Backhaus 3 studying the "Influence of Feed and Individuality on 

 the Taste and Healthfulness of Milk," says that a number of plants 

 influence the color of milk and butter. The same author conducted 

 several pigment feeding experiments with cows. Negative results were 

 obtained with respect to the milk when feeding Fuchsin, Bismark 

 brown, and curcuma powder, although the feces showed the pigments 

 abundantly. When feeding sodium fluorescin the urine was affected 

 but not the milk. When feeding methyl violet, however, the author 

 was able to show that this pigment was carried into the milk fat in 

 a reduced condition so that on contact with the air and with the aid 



1. Jour. Biol. Chem. 13, No. 1, p. 72 (1912). 



2. Zeit. f. Biol. 45, 353 (1904). 



3. Berichte, Landwirt. Inst. U. Konigsberg 5 (1900). 



