THEORIES OF IMMUNITY. 



ing to determine what these functions were 

 Bordet first called attention to the occurrence of 

 the so-called " precipitines." (Ann. de V Inst. 

 Past., 1899, T. XIIL, p. 225.) He found that in 

 treating rabbits with chicken's blood, a hemolytic 

 serum could be obtained; but also, that when 

 this hemolytic rabbit's serum was added to 

 chicken's blood a precipitate made its appear- 

 ance. 



Many such precipitates have been obtained 

 with many kinds of blood, and also with many 

 kinds of bacteria as well. Their nature is not 

 well understood, but the reactions seem to be 

 specific and most exact, and these reactions are 

 of great medico-legal value in the determination 

 of the presence of human blood in suspected 

 stains. 



The general reaction may be shown by the 

 same formulas as were used for the purpose of 

 illustrating the forms of immunity as follows : 



The production of the precipitate requires : 



1. The blood globule, molecule^H+X+X 



2. The immune body, " = H+iJ+X 



3. The complement, " = ZT+P+X 



9G 



