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 or killed by the use of chem- 

 ical agents, 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 and in chronic infections of the genito-urinary 

 tract. The material may be used in the form of "personal" or "auto- 

 genous" and "stock" vaccines. An autogenous vaccine is one prepared 

 from 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. 



