134 



BACTERIOLYS1NS AND HEMOLYSINS 



The specificity of the bacteriolytic process depends, therefore, on the 

 specificity of the cytophile group, while the complementophile group 

 possesses no or, strictly speaking, only slight specificity; it adapts itself to 

 the complements of very many though not quite all kinds of animals. 



Recent experiments have proven that the complement consists of 

 two different parts, the middle piece and the end piece. 



Technique of Bacteriolytic Experiments. 



To determine the occurrence of bacteriolysis there are two methods of 

 procedure : 



1. Pfeiffer's experiment. 



2. The bactericidal plate method. 



I. The Pfeiffer's Experiment. 



The essentials of Pfeiffer's experiment have been described at the 

 beginning of this chapter. Briefly, it consists in injecting intraperito- 

 neally, in a normal animal, bacteriolytic immune serum mixed with living 

 bacteria. The resulting bacteriolysis is studied microscopically by with- 

 drawing small amounts of peritoneal exudate from time to time. If 

 this experiment is performed with various dilutions of immune serum, and 

 if it be determined at what dilution bacteriolysis fails to occur, then the 

 bacteriolytic titer is evident. 



The details can best be understood by taking a practical example. It 

 is desired to find the bacteriolytic titer of the serum of a patient recovering 

 from typhoid fever by means cf the Pfeiffer experiment. 



To accomplish this task the following ingredients are needed: 



1. A strain of bacillus typhosus of known virulence for guinea-pigs. 



2. Patient's serum, sterile, and free from complement. 



3. Guinea-pigs of 250 gms. weight. 



A preliminary experiment must be performed in order to determine the virulence 

 of the typhoid strain. 



TESTING THE -VIRULENCE OF STRAIN. 



. _ , 



' ' -'".' ' 

 Guinea-pig No. i. I i/II '09 One loopful of a typhoid agar culture suspended in j 2/II dead. 



Guinea-pig No. 5. j i/II '09 One-tenth loopful of same, 



2/II sick. 

 3/II well. 



