PUTREFA C TION A ND PUS- FORM A TION. 289 



powder, chloride of lime, tar oil, and chloride of zinc, 

 in periods varying from two to nineteen days ; while 

 pieces of meat exposed in the same way in bottles 

 containing carbolic acid powder, carbolic acid, and 

 cresylic acid only dried up without becoming tainted 

 at all These observations have been confirmed by 

 many other experimenters. 



But, in order to accept Lister's theory, we must con- 

 sider it proved not only that bacteria are the cause of 

 putrefaction, but that pus-formation depends upon 

 irritation, and that putrefactive change exerts the par- 

 ticular irritation which is prone to excite the develop- 

 ment of pus. Whereas it seems more reasonable to 

 conclude that the carbolic acid which kills the bacte- 

 ria also destroys the life of the pus corpuscle. 



The occurrence of putrefaction is considered by 

 Lister to be the starting point of pyaemia and some 

 other morbid phenomena, but it has surely escaped 

 the notice of the advocate of this hypothesis that, 

 on the one hand, we may have the putrefactive change 

 without pyaemia being occasioned, and on the other, 

 the latter condition brought about independently of 

 putrefaction ; just as we may imbibe the most disas- 

 trous fever poisons without being annoyed with the 

 least unpleasant smell, and experience the most dis- 

 gusting odours without suffering in the least degree 

 from any septic poison. 



But it has not been proved that pus-formation is 

 invariably accompanied and preceded by the develop- 



