68 VACCINE AND SERUM THERAPY. 



cines for Streptococcus pyogenes, Mic. pneumoniae and, accord- 

 ing to some, for the Mic. gonorrhoeae. 



Some investigators have used vaccines containing several 

 species of bacteria. Serum and vaccine manufacturers have pre- 

 pared vaccines suitable for active immunization against one or 

 many different sepcies. Wright at one time made no particular 

 effort to identify the species of the causal organism, simply mak- 

 ing a vaccine from the cultures obtained by inoculation with 

 material from the lesion. This is open to many objections, for 

 at times the causal organisms may be such that it will not grow 

 on ordinary media or else the causal organisms may not grow as 

 well as secondary invaders and saprophytic species. Because of 

 the mixed and undetermined vaccines used in immunization it 

 may frequently happen that those organisms, for which immuni- 

 zation is necessary or beneficial, are not injected. 



In all cases it ought clearly to be remembered that if bene- 

 fits are to be derived from active immunization the vaccine must 

 consist of a suspension of the causal organism. To determine 

 these, microscopic examinations of the material from the lesion, 

 and isolation of the organisms when possible ought to be made. 

 This cannot be too strongly emphasized, especially to the practi- 

 tioner who can buy from the druggist vaccines said to be good 

 for boils, acne or whatever the condition may be, while as a mat- 

 ter of fact the vaccine may not contain the organism causing the 

 particular lesion which is to be recovered from as a result of active 

 immunization. This has undoubtedly been the cause of some of 

 the failures observed by some clinicians and has, as was the case 

 with tuberculin, decided the practitioner against the use of bac- 

 terial vaccines in certain cases of infection in which vaccine might 

 have been of value. 



PREPARATION OF BACTERIAL VACCINES. 



While killed cultures of bacteria have for some time been 

 used in active immunization, the amounts injected had been only 

 indefinitely determined. Wright and Douglas originated and de- 

 scribed a method for the preparation and standardization of bac- 

 terial vaccines to be used in immunization. The causal organisms 

 according to this method are grown on artifical culture media 

 after which they are suspended in sterile salt solution. The num- 



