HMMOLYSINS. 35 



agglutinates typhoid and cholera bacilli. Bordet 

 could show that the bacterial agglutinins are gov- 

 erned by the same laws of combination that Ehr- 

 lich and Morgenroth showed governed the inter- 

 bodies of normal sera. Thus if to a normal serum 

 which agglutinates both typhoid and cholera ba- 

 cilli some typhoid bacilli be added and the mixture 

 centrifuged, the clear fluid will no longer be able 

 to agglutinate typhoid bacilli. It will still, however, 

 readily agglutinate those of cholera. The typhoid 

 agglutinin has in this way been tied to the typhoid 

 bacilli first added, and with them it has been car- 

 ried down in the centrifuged sediment. If the 

 experiment be reversed, so that cholera bacilli are 

 first added and then the mixture centrifuged, the 

 clear fluid will contain the typhoid agglutinin, but 

 not that of cholera. These points, brought out by 

 Bordet for bacterial agglutinins, I have had Mal- 

 koff study regarding the haemagglutinins of nor- 

 mal serum, and this investigator has found the 

 same facts to apply to these substances. To nor- 

 mal goat serum, which agglutinates the red cells 

 of man, rabbits, and pigeons, he added human red 

 cells and then centrifuged the mixture. In this 

 way the agglutinin for these cells was abstracted 

 from the serum, which then was capable of agglu- 

 tinating the red cells of rabbits and pigeons, but 

 incapable of agglutinating human red cells. When 

 he used pigeon blood instead of the human blood, 

 the agglutinin for pigeon blood was abstracted, 



