318 



GENERAL MICROBIOLOGY 



C. POLYVALENT BACTERINS 



Polyvalent bacterins are those which are prepared from 

 several species of bacteria, e.g., M. (Staph.) albus, M. 

 (Staph.) aureus, Strep, pyogenes, etc. 



The suspension of each must be prepared and standard- 



FIG. 72. Blood-counting Apparatus for Use in Standardizing Bacterial 



Vaccines. 



ized separately, and then the emulsions of all mixed. In 

 this way, it is possible to have a known number of each 

 species in the resulting product. 



REFERENCES 



FITCH C. P.: A Review of the Principal Methods Used to Standardize 



Bacterins (Bacterial Vaccines). Report of the N. Y. State Vet. 



College for the year 1913-1914, pp. 207-219. 

 MCCAMPBELL: Laboratory Methods for the Experimental Study of 



Immunity, pp. 186, 188. 

 STITT: Practical Bacteriology, Blood Work and Parasitology, 2d 



Ed. (1911), pp. 143-145. 

 KOLMER: Infection, Immunity and Specific Therapy (1915), pp. 611- 



661. 

 ZINSSER: Infection and Resistance (1914), pp, 328-357. 



