THE HISTORY OF BACTERIOLOGY. 443 



knowledge. Among others Lancisi, Reau- 

 mur, Linne" and Plenciz gave their adhesion 

 to the theory, Plenciz in 1762 advancing com- 

 prehensive reasons for it. The investigations 

 of Pringle upon infectious diseases and disin- 

 fectants also belong to this period. The doc- 

 trine, however, soon became discredited, be- 

 cause of the growth of the opinion that not 

 merely the causers of disease were alive and 

 parasitic, but the diseases themselves were 

 parasites ; names like lupus and cancer still 

 remind us of this. Of even greater influence 

 was the fact that the study of pathological 

 anatomy under Malpighi, Bichat and Virchow 

 busied itself only with the consideration of the 

 anatomical changes in disease, and lost all 

 comprehension of the outside factors. This 

 went so far that only in 1874 did Virchow 

 express a very restricted recognition of the 

 parasitic theory of infectious disease. 



The question how far microbes are con- 

 cerned in the processes of putrefaction and 

 fermentation approached the matter on quite 

 another side. Some asserted that the infu- 

 soria and moulds on account of their ubiquity 

 were a ^v^oo^a naxov jSoro?, a bad fermentation 

 product of the soil, originated by spontaneous 

 generation, while others derived them legiti- 

 mately from germs of the same kind. Micheli 



