28 VACCINE AND SERUM THERAPY 



medicine and for the determination of proteid material 

 for forensic purposes. 



Bactericidal and Bacteriolytic Tests. — The bac- 

 tericidal and bacteriolytic powers of an animal's 

 serum may either be tested in the animal's body or 

 in a test-tube. The in vivo test is known as Pfeiffer's 

 phenomenon. This depends upon the fact that 

 bacteria, when injected into the peritoneal cavity of a 

 guinea-pig, together with a homologous immune 

 serum, undergo dissolution. As practised, the test 

 finds a double application. It may be done to 

 determine the bacteriolytic power of a given serum 

 against a known organism, or for the identification of 

 a particular micro-organism by means of its suscepti- 

 bility to lysis in a known immune serum. 



Hemolytic Tests.— Determination of the hemolytic 

 action of blood serum, bacterial filtrates, and of a 

 variety of other substances, such as tissue extracts 

 and animal and plant poisons, have frequently to be 

 made. 



Fixation of the Complement Test.— This test is 

 extensively used both in bacteriological investigations 

 and in practical diagnosis for the determination in 

 serum of specific antibodies. 



