AGGLUTININS 53 



ment and the bacteria. The same chemical union occurs between 

 the red cells and the immune body in haemolysis, but not between 

 the cells and the complement. 



Ehrlich holds that there are many complements, each one dif- 

 ferent from the other, and that their action is specific for the 

 different kinds of bacteria or cells with which an animal may be 

 immunized. Bordet and Buchner, on the other hand, maintain 

 that there is but one complement. 



The solution of any cells by immune bodies, or anti-bodies, as 

 they have been called, is known as cytolysis. And cytolysins 

 may be produced by making anti-bodies of nerve cells, leucocytes, 

 epithelial cells, liver cells, as well as blood cells, by immunizing 

 an animal against these different cells with repeated injections 

 of the cells or emulsions of them. 



Agglutinins are peculiar bodies which have the property of 

 causing certain cells to agglutinate. One of the earliest manifes- 

 tations of immunity of a certain serum to bacteria, or to blood 

 cells, is this peculiar action of the serum causing either the bac- 

 teria or blood cells to clump together in masses. Part of Pfeiffer's 

 reaction is the agglutination of the cholera spirilla in clumps 

 before they are dissolved by the complement and immune body. 



Recent studies accord to agglutinins one of the most impor- 

 tant places in the defense against disease. Their action is 

 believed to facilitate that of lysins and opsonins, helping the 

 latter by fixing a group of bacteria so that they may be the 

 better prepared for phagocytosis. 



If the serum of a typhoid fever patient is mixed, even in high 

 dilutions with some typhoid bacilli, the latter are clumped in 

 isolated groups. Clinically this is known as the Widal reaction, 

 and is the most reliable single sign of typhoid fever. 



These agglutinins may be produced artificially by injecting 

 large and increasing doses of bacteria into animals. After a time, 

 in the serum of the rabbit, there develops a peculiar body which 

 agglutinates typhoid bacilli, if they are brought in contact with 





