FUNGI. 



289 



its end, but the bacillus is the only one found in the 

 blood, and is really characteristic of the disease. 

 Many are the causes to which cholera has been attri- 

 buted. Trouessart says that " the essentially epidemic 

 and contagious progress of this disease clearly indi- 

 cates the presence of a microbe, of which the chosen 

 seat is the intestines, whence it passes with the 

 patient's faeces, and constitutes the contagious element 

 in places affected by the epidemic." Koch was the 

 first to describe the microbe which is considered to 

 be the producing agent of cholera, and he called it 

 the "comma bacillus," after its form (Fig. 56). He 

 cultivated it successfully in several media, but for a 



Fig. 56.— Comma Microbe {Trouessarf). 



long while all attempts at inoculating animals by in- 

 jection of the bacillus failed. Subsequently cholera 

 was thus produced in guinea-pigs, dogs, etc., which died 

 at the end of two or three days, with the intestines 

 containing a number of vigorous comma bacilli. In 

 1884 Ferran conducted a series of experiments at 

 Toulon, and professes to have obtained an attenuated 

 microbe for preventive inoculations. He believes that 



U 



