THE MANUFACTURE OF VACCINES. 479 



To prepare a bacterial vaccine, as based upon the opsonic theory, 

 the specific organism is isolated and after being grown for twenty-four 

 hours at a temperature of 37, it is emulsified in sterile physiological 

 salt solution, heated for one half hour at 60, standarized as to the number 

 of bacteria present in i c.c. of the emulsion and a preservative added. 



If the patient and attending physician are conveniently situated in 

 respect to a laboratory, the "opsonic index" may be taken' before and 

 during the treatment. This consists in the determination of the average 

 number of the given species of bacteria ingested by the leucocytes of the 

 patient, as compared to that which the leucocytes of normal blood are 

 capable of destroying. It is usually found that immediately following 

 the injection of a specific bacterial vaccine there is a "negative phase" 

 during which the leucocytes of the patient destroy a smaller number of 

 bacteria. This is followed by a "positive phase," which gradually tends 

 to return to normal. 



The use of bacterial vaccines has yielded excellent results, especially 

 in the treatment of furunculosis, acne, sycosis and other affections caused 

 by pyogenic organisms. The material may be used in the form of "per- 

 sonal" or "autogenous" and "stock" vaccines. An autogenous vaccine 

 is one prepared frqm a culture of the specific organism isolated from the 

 case under treatment. The latter products, which are prepared from 

 stock cultures of the specific organisms, may be manufactured and placed 

 in stock until needed for use. 



