THE SENSITIZERS OF SERA. 253 



produces no such effect. We do not agree, therefore, with F. Ham- 

 burger on this point. 



One of the principal properties of antimicrobial and of hemolytic 

 sensitizers is their specificity. As a general rule immune sera are 

 active only against those cells which by injection have given rise 

 to them. There is, we believe, no exception to this rule, although 

 Ehrlich and Morgenroth have noted that the serum of rabbits 

 treated with ox blood sensitizes not only ox corpuscles, but also 

 goat corpuscles. 



On the other hand there are numerous exceptions to this rule 

 among the coagulins. Wassermann and Schutze,* Stern, t and 

 Nuttall $ in particular have shown that the serum of animals in- 

 jected with human serum precipitates not only this serum, but also 

 the serum of anthropoid apes. Griinbaum, § by injecting rabbits 

 with the sera from three different species of monkeys, obtained sera 

 affecting the serum of these three species and also of man. Linos- 

 sier and Lemoine || found that the serum of animals given ox serum 

 would precipitate sera of other animal species. And Moro^j has 

 recently shown that a serum that precipitates cow milk will also 

 precipitate goat milk. 



It seemed to us well to determine to what extent our sera active 

 against albuminous substances were endowed with specificity, par- 

 ticularly as regards their sensitizing property. 



Rabbit serum active against milk. — This serum from rabbits 

 that had been given injections of cow milk was heated to 56 degrees 

 and added to different milks: cow milk, ewe milk, goat milk, mare 

 milk and human milk. 



With each milk, mixtures were made with normal rabbit serum, 

 56 degrees, and with specific serum, 56 degrees. 



Tube 1 Milk (e.g., cow) 0.2 c.c. 



Serum rabbit > milk, 56 degrees 0.6 c.c. 



Alexin (rabbit) 0.1 c.c. 



Tube 2 Milk 0.2 c.c. 



Serum normal rabbit, 56 degrees 0.6 c.c. 



Alexin 0.1 c.c. 



* Wassermann and Schutze. Berlin klin. Wochen., XXXVIII, 1901, 187. 



t Stern, Deutsche med. Wochens., 1901, p. 135. 



J Nuttall, The Journal of Hyg., July, 1901, 3. 



§ Griinbaum, The Lancet, January 18, 1902. 



|| Linossier and Lemoine, Cornptes rend. Soc. de Biol., 1902 85. 



If Moro, Wiener klin. Wochsch., 1902, 121. 



