70 THE BACTERICIDAL SUBSTANCES OF THE BLOOD 



A. Determination of the Strength of the Bacterial Emulsion which 

 Serves as a Basis of the Experiment. The emulsion in question 

 is diluted in the proportion of 1 to 100,000, and 5 c.c. of the 

 resultant dilution distributed over the surface of plates. The 

 number of developing colonies is then counted. The result shows 

 the following: 



Type. 



Cholera vibrios 



Typhoid bacilli 



5 c.c. of a 1 to 100,000 

 dilution contain: 



1 c.c. of the undiluted emulsion 

 hence contains: 



Plate I 

 Plate II 



20 . organisms 

 21 .0 organisms 



Average 21.5 organisms 410,000 organisms 



Plate I 

 Plate II 



21.0 organisms 

 30 . organisms 



Average 25 . 5 organisms 510,000 organisms 



B. Estimation of the Bactericidal Strength of the Serum. Equal 

 quantities (1 c.c.) of the undiluted serum and of various dilutions 

 of the original emulsion are mixed and after twenty-four hours' 

 exposure plated out, when the number of developing colonies is 

 counted. 



Type. 

 Cholera 



Typhoid . . 



1 c.c. of serum thus kills: 



About 410,000 organisms 



About 5100 organisms 



A good idea of the progress of bacteriolysis, and the gradual gain 

 of reproduction over destruction, when the amount of serum was 

 insufficient at the start to kill all the organisms, as also of the 

 differing resistance which different strains of organisms offer to the 

 destructive forces of the serum, may be had from the study of 

 the following table (taken from Trommsdorff). The figures in 

 general represent the variations noted in different tests; those of 



