THE TECHNIQUE OF SERUM REACTIONS 255 



In the actual test with bacterial filtrate, the procedure is as follows: 

 In a series of narrow test tubes, the following mixtures are made: 



Tube 1. Antibacterial serum .5 c.c. + bacterial filtrate 1. c.c. 

 " 2. Normal serum .5 c.c. + bacterial filtrate 1. c.c. 



" 3. Antibacterial .serum .5 c.c. + salt solution 1. c.c. 

 " 4. Salt solution .5 c.c. + bacterial filtrate 1. c.c. 



Place the tubes in the incubator at 37.5° 0. In a positive test, tube 

 1 only should show a haziness which develops into a distinct cloudiness 

 or even a flocculent precipitate within one hour. Tubes 2, 3, and 4 

 should remain clear. 



For the testing of an unknown proteid with the serum of an animal 

 immimized with the proteid sought for, the technique of the test is as 

 follows: 



1. 0.1 c.c. immune serum + 2 c.c. unknown proteid solution. 



2. 0.1 c.c. immune serum + 2 c.c. known proteid solution of variety suspected 



(similarly diluted). 



3. 0.1 c.c. immune serum + 2 c.c. proteid solution of different nature (similarly 



diluted). 



4. 0.1 c.c. immune serum + 2 c.c. salt solution. 



5. 2 c.c. unknown proteid solution. 



The test is positive when a precipitate appears in tube 1 aiid in tube 

 2, but not in any of the others. The precipitate should appear definitely 

 within fifteen to twenty minutes. 



Bactericidal and Bacteriolytic Tests. — ^The bactericidal and bac- 

 teriolytic powers of serum may be tested either in the animal body 

 or in the test tube. The most common bacteriolytic test, in vivo, is 

 that which is known as Pfeiffer's test. This test depends upon the 

 fact considered in a previous section, that bacteria, when injected 

 into the peritoneal cavity of a guinea-pig, together with a homologous 

 immune serum, undergo dissolution. 



As practiced in bacteriological work, the test finds a double appli- 

 cation. It may be carried out either for the determination of the 

 specific bacteriolytic power of a given serum against a known micro- 

 organism, or for the identification of a particular microorganism by 

 means of its susceptibility to lysis in a known immune serum. 



1. Determination of the bacteriolytic power of serum against a 

 known microorganism in vivo : ^ 



1 P. Th. Mailer, " Teehnik d. serodiagnos. Methoden," Jena, 1909. 



