276 PHARMACEUTICAL BACTERIOLOGY 



II. Phylacogens 



Phylacogens are sterile aqueous solutions or suspensions of metabolic 

 substances or derivatives generated by bacteria grown in artificial culture 

 media. The bacteria are then killed and filtered through clay filters. 

 Each specific phylacogen consists of equal parts of the products of the 

 infection and a pure culture of the principle infecting organism. Their 

 use is based upon the idea of Dr. Schafer who holds the opinion 

 that most, if not all infections, are mixed, instead of simple, and that the 

 organisms associated with the chief infecting organism play an equally 

 important part in the disease and in developing the immunization. A 

 number of these preparations have been tried out in practice but the only 

 one which appears to have met with any considerable success is the one 

 for rheumatism. 



12. Mixed Bacterins. Polyvalent Bacterins 



These have been sufficiently explained under sensitized bacterins. 

 It would appear (as indicated under 11) that certain infections are nor- 

 mally multiple. In such cases it is manifestly unreasonable to expect best 

 results from a univalent bacterin, made from one of the several infecting 

 organisms. Unless it can be proven experimentally that one particular 

 organism in a multiple infection is the primary cause, it is to be assumed 

 that the best effects are to be obtained from a bacterin made up of all 

 of the infecting organisms, combined in about the same proportion as they 

 occur in the infection. Such mixed bacterins have been tried out in^ery- 

 sipelas and in cancer, but apparently without any considerable success. 



