50 IMMUNE SERA. 



fore be followed by severe disturbances, particu- 

 larly, however, by a decreased resistance against 

 infectious diseases. The author succeeded in dem- 

 onstrating that animals injected with anti-comple- 

 ments to tie up their complements were much less 

 resistant to certain infectious diseases. 



The spontaneous development in an animal of 

 auto-anticomplement, i.e., substances developed 

 within the organism against its own complements, 

 has not yet been demonstrated. Ehrlich and Mor- 

 genroth were able in a rabbit to excite the produc- 

 tion of an auto-anticomplement by treating the 

 animal in a certain way. Ordinarily, normal rab- 

 bit serum is slightly solvent for guinea-pig blood. 

 If the rabbits are treated with goat serum, the rab- 

 bit serum loses this solvent power for guinea-pig 

 red cells. Even if fresh normal rabbit serum is now 

 added the hsemolysis does not take place, although 

 we know that this fresh serum is haemolytic. This 

 shows that in the serum of the rabbit treated with 

 goat blood an anti-complement has been formed 

 which combines with the complement of normal 

 rabbit blood, for it was able to inhibit the action 

 of the complement of the normal freshly added 

 rabbit serum. In the rabbit's body, then, as a result 

 of this procedure, an anti-complement has been 

 formed against the complement of its own serum, a 

 true auto-anticomplement. 



Now, according to the side-chain theory, there 

 are no receptors in an organism for the complements 



