BACTERICIDAL ACTION OF NORMAL SERUM 197 



EXAMPLE 2. Bacillus dysenteries (Flexner). Inoculation with 

 0-0002 c.c. 21-hour bouillon culture of B. dysenteries (Flexner). 



Here again 0-001 c.c. of dead bouillon culture has a distinct effect. 



EXAMPLE 3. Bacillus typhosus. Inoculation with 0-00006 c.c. 

 21-hour bouillon culture of B. typhosus. 



In the case of B. typhosus 0-01 c.c. of dead bouillon culture 

 produces a distinct effect ; in other experiments we failed 

 to obtain any distinct reduction with 0-001 c.c. The table 

 brings out a peculiarity which we have always found in the 

 case of B. typhosus with guinea-pig's serum, namely, a want 

 of complete killing off by the higher quantities. If we com- 

 pare, for example, these results with those in the case of 

 V. MetchniTcovi (Example 1), we find in both instances almost 

 the same number of colonies left with 0-1 c.c. of serum; 

 0-2 c.c. of serum kills off completely the V. Metchnikovi, 

 but leaves seventy-three colonies of B. typhosus, and even 

 0- 3 c. c. fails to kill it completely. In the strain of B. typhosus 

 culture used there are apparently a small proportion of 



