viii.] THE INFECTIVENESS OF CHOLERA. 153 



cholera-dejecta, for herein the comma-bacilli do not become 

 perfectly dry, and therefore are not dead. Convalescent 

 and weakly persons in hospitals, side by side with cholera- 

 patients voiding innumerable masses of comma-bacilli on to 

 the bed-clothes and the floor, would have very little chance 

 of escaping infection. Yet this immunity is observed over 

 and over again. In the Medical College Hospital at 

 Calcutta I have noticed this, that cholera patients were 

 placed in the general ward side by side with other patients : 

 the native non-cholera patients, like other natives, eat their 

 meals with their fingers, using no spoons or forks, yet I 

 have not heard of any of these convalescents, or the nurses, 

 or anybody else among the attendants, having become 

 infected with cholera. The same thing has been ex- 

 perienced in London and other places during various 

 epidemics. When in India in any city or village a case of 

 cholera occurs, except in the cholera-season, the disease 

 does not spread, yet amongst the natives the constant and 

 close attendance of the relatives on the sick is notorious ; 

 no special precautions against contamination with cholera- 

 dejecta are taken, yet no infection occurs. These are 

 conditions which obtain everywhere, and which have been 

 pointed out and demonstrated over and over again in India 

 during non-cholera seasons. If the fresh cholera-dejecta 

 or if the comma-bacilli were the infective agents, such things 

 could not be. Again, as has been already pointed out, the 

 water of the tanks becomes constantly contaminated with 

 cholera-dejecta and therefore also with abundance of the 

 comma-bacilli, and although the water of these tanks is 

 universally used by the people living around them, yet in 

 non-cholera seasons no spread of cholera occurs. I will 

 here give two such instances that came under my own 

 observation in Calcutta in 1884. 



