BY R. GREIG SMITH. 



301 



A repetition of the experiment with a slight variation wi 

 made and similar results were obtained. 



These experiments show that bacteria when treated with the 

 so-called chemical agglutinating agents are not capable of being 

 absorbed by the phagocytes. 



The conclusions to which this research has led are as follows: — 



1. Normal typhoid bacteria are incapable of being absorbed by 

 the leucocytes when these have been freed from adhering serum. 



2. Typhoid bacteria, when treated with active agglutinating 

 serum which has been heated to destroy the opsonins, are agglu- 

 tinated and are then englobed by the leucocytes. 



3. Typhoid bacteria which have been grown in agglutinating 

 serum, heated or not heated, are also absorbed. 



4. While active agglutinating serum prepares the microbes for 

 inception by the phagocytes, the so-called chemical agglutinating 

 substances do not possess this property. 



5. The function of agglutinin is, therefore, to coat the bacteria 

 with a precipitate which is positively chemiotactic towards the 

 leucocytes, and thus, by facilitating the absorption of the microbes, 

 agglutination plays an active part in immunity. 



