THE MICROBKS OF HUMAN DISEASES. 



203 



Ferran regards this peronospora as the infectious 

 agent of cholera. Yet it seems extraordinary that 

 such a remarkable polymorphism should have escaped 

 the observation of Koch and of the numerous micro- 



Figs. 88, 89, 90. Evolution of cholera microbe (Pernnospora Ferrawi: Ferran") : 

 1. Cholera microbe (Ilacillus kumma), discovered by Koch. 2. Spiral form of 

 bacillus, transferred from gelatine to an infusion. 3. Degeneration of spiral 

 form after a series of successive cultures. 4. Cholera microbe (Peroiiospora 

 Ferrani): development of oogonium on the spirilla and straight filaments. 

 5. I he oogonium is filled with granules which centre in a point k, and it is then 

 converted into an oosphere ; m, poilinidiuiu on fertilizing o gan 6. The oospuere 

 is converted into mulberry-shaped and comma-shaped bodies. 



graphists who have made various cultures of the 

 comma bacillus. It is difficult not to suppose that 

 some negligence or error has vitiated Ferran's re- 



