~)Q Biological, Chemical and Physical Characteristics of Milk. 



This however does not end the degree of the specificity, as it is possible with the aid 

 of the precipitation method to differentiate various kinds of proteids of one and the 

 same milk. If the soluble proteid bodies are separated from the undissolved casein by 

 filtration (Schlossmann), then the rabbits which are treated with soluble proteid bodies 

 furnish sera which react only to milk albumin and globulin (Hamburger). 



It is of further interest that cow-casein sera gave precipitation 

 with cattle blood (Hamburger), the same as is the case with lac- 

 tosera (Landsteiner, Halban, Dungern, F. Meyer, L. Aschoff). 



Moreover lactosera immobilizes spermatozoa of bulls, and 

 dissolves red blood corpuscles of cattle. However no reaction 

 results from the addition of cattle blood serum containing anti- 

 bodies to cow milk (Meyer). The anti-serum sensitized against 

 cattle blood only gives slight precipitation when it possesses espe- 

 cially high value (Uhlenhuth and Sclmtze). The same conditions 

 were found in preparations of human blood, and women's milk, by 

 Halban and Landsteiner. 



Uhlenhuth and Sclmtze proved that the differentiation of 

 various kinds of milk shows that the biological method succeeds 

 even when the milk is heated to a high temperature (114 deg. C. in 

 an autoclave) ; if the milk antigen was heated 20 minutes at 120 

 deg. C., lactosera resulted, which only contained coagulins, but no 

 hemolysins. Sion and Laptes showed that the most varied splitting 

 and decomposing changes of cheese-making and cheese-ripening 

 do not influence the antigen to such an extent that the kind of milk 

 used in making the cheese could not be determined by the biological 

 method. This specificity is of course manifested even in the use 

 of lactosera, but is not absolute, only relative. Lactosera also gave 

 a reaction with the milk of closely related animals, the same as 

 has been established for blood sera, meat sera, etc. Thus for in- 

 stance it is impossible to differentiate sheep's milk from goat's 

 milk (Uhlenhuth, Moro, Gengou), although it is possible to draw 

 conclusions from the comparison of the intensity of the reaction 

 in the homologous milk. 



Other authors, as for instance Bauer, succeeded in demonstrat- 

 ing by the so-called complement-fixation method, the presence of 

 cow's milk in woman's milk, even when only 1 c. c. of the former 

 had been added to 1000 c. c. of the latter. 



If specific serum which has been heated for a half hour at 57 

 deg. C. is mixed with milk and as much complement is added as 

 is necessary for the dissolving of the subsequently added blood 

 corpuscle suspension, with the aid of certain quantities of hemo- 

 lytic amboceptors, then the amboceptors of the lactoserum bind the 

 complement, provided they find in the milk the specific antigen 

 (cow lacto serum-cow milk), and the subsequently added hemolytic 

 system, free of complement, no longer finds complement, so hemo- 

 lysis does not occur, but instead fixation of complement results. If 

 there is no specific antigen present (if the milk to be examined con- 

 tains no cow milk), the complement remains free to be utilized 

 later by the hemolytic amboceptors and the blood cells, for the 



