458 



SPIRILLUM CHOLERJE ASIATICS. 



3. Influence of 



drinking 



water. 



Insects. 



5. Habits of 

 life. 



Cleanliness. 



unsuitable character of the soil, cleansing of the surface 

 of the soil, &c., it is much less important than many other 

 factors. 



3. The mode in which the population obtain their 

 drinking and household water is at times of great impor- 

 tance. If the water has in the first instance become 

 contaminated with comma bacilli it forms for a short 

 time a dangerous source of infection, which leads in the 

 simplest and most direct manner to the exposed indivi- 

 duals. The establishment of this source of infection 

 may be greatly favoured by the situation of the well, and 

 its mode of formation ; especially where water is carried 

 to it from the surface of the soil, or where canals or 

 gutters from cesspools, &c., lead to the well. The more 

 of these badly constructed wells there are in a town the 

 more readily will cholera be spread by the water. Open 

 and stagnant collections of water are naturally the most 

 dangerous ; in Lower Bengal such collections form the 

 source of the water supply, and appear, as a matter of 

 fact, to be one of the most frequent and dangerous 

 sources of infection. Where the wells are deep and 

 well constructed, so that they cannot be contaminated 

 from the surface of the soil ; or where the water is carried 

 by well-constructed pipes, this mode of spread of the 

 infective material is practically absent. 



4. Insects deserve especial mention, as they vary 

 extremely in numbers according to place and season, 

 and form in all probability a by no means unimportant 

 mode of conveyance of the poison, a mode which increases 

 or diminishes according to the number and varieties 

 of the insects. No quantitative estimate can be formed 

 with regard to this factor. 



5. Certain habits of life can in the case of one nation 

 furnish greater opportunities for the spread of cholera 

 than in that of another. The average cleanliness of 

 the population has the greatest influence in this respect. 

 The more cleanly the method of handling the sick and 

 the infected clothes, the more- carefully contamination 

 of the soil, of the water, and of various other objects with 

 the dejecta is avoided, the fewer will be the sources of 



