QUATERCENTENARY STUDIES IN PATHOLOGY 



Filtrate from 30 day old culture. 



Filtrate from 60 day old culture. 



From these experiments, it is manifest that even larp^e doses of 

 filtrates of cultures of various ages fail to produce lethal effects. It 

 was considered that increase in virulence of the cultures might lead to 

 increased toxin production, and to this end the bacillus was passed 

 through several series of guinea-pigs and rabbits, cultures being ultimately 

 made from the last members of the series. Filtrates of these cultures 

 were found to be incapable of producing lethal effects in doses up to 

 40 C.C for guinea-pigs and 50 c.c. for rabbits. Wassermann has suggested, 

 that although the toxin is largely a secretory product of the bacillus 

 pyocyaneus, it may be kept back in the mucinous material, and in 

 this way be prevented from passing the filter. This, however, does 

 not apply to young cultures up to the first seven days, and here, as 

 the experiments show, a soluble toxine, if such exist, is present only 

 in very minute quantities. 



Action of dead cultures of B. Pyocyaneus. 



Dead cultures prepared in various ways were used in a number 

 of experiments. Following Wassermann, the cultures were grown on 

 bouillon or on agar. The bouillon cultures, after 2, 7, 21, 31 and 60 days, 



(164) 



