Precipitin. 55 



gen, but as a proteid-containing material it is an antigen in itself, 

 or rather a collection of antigens, which may again produce anti- 

 bodies in the body of an animal. These anti-bodies against milk 

 not only develop in artificial administration by injections, but also 

 under certain conditions during the natural ingestion of the milk 

 per os as a food. Although usually such anti-bodies against nutri- 

 tive proteids of unlike origin appear only in intensive over-feeding 

 of proteids (Ascoli, Michaelis and Oppenheimer, Uhlenhuth, and 

 others), nevertheless in the presence of an injured intestinal 

 mucous membrane the absorption of proteids of unlike origin may, 

 under natural conditions, take place, and thereby induce the for- 

 mation of anti-substances. 



Moro succeeded in finding cow milk precipitin in two instances, 

 and milk proteid in one instance in an examination of 22 anemic 

 bottle-fed children. 



Bauer found precipitating substances of cow's milk in the 

 blood of an emaciated man. 



Kentzler, with the aid of the precipitation test, demonstrated 

 milk proteids in the blood of six human subjects in which the gas- 

 tric secretion was disturbed, out of 61 cases that he examined two 

 to three hours after feeding. 



Although milk is absorbed through the intestines of older 

 individuals only after the splitting up of the proteids, nevertheless 

 in case of an injured mucous membrane, or in greatly emaciated 

 and in very young individuals the direct absorption of unchanged 

 proteids is possible. Ganghofner and Langer succeeded in proving 

 this on very young rabbits, on pigs and on newly born cats, and 

 they succeeded also in demonstrating a precipitin formation in the 

 blood. Schkarin describes similar results after the feeding of 

 cow's milk to young rabbits. 



Lactoserum. 



It will be advisable and appropriate to include at this place 

 a subject which as a matter of fact belongs to the chapter dealing 

 with the characteristics of the milk of various species of animals. 

 Milk is an antigen and contains various antigens. After injecting 

 the milk of species A into an individual of species B, the formation 

 of various anti-bodies, precipitins, amboceptors, etc., may be ob- 

 served in the blood serum of the treated individual, which gives 

 to the blood serum the specific characteristics of lactoserum. This 

 specific characteristic is shown by the fact that the cow lacto- 

 serum of rabbits produces a precipitation only when cow's milk 

 is used for the precipitation, but not with milk of women or goats. 

 Works of Bordet, Fish, Morgenroth, Wassermann and Schiitze 

 show the specific action of lactosera. With the aid of such sera 

 the possibility is afforded of differentiating the milk from various 

 species of animals. 



