178 APPLIED BACTERIOLOGY 



of a waterworks, the results may be very disastrous and 

 far-reaching. In some waters cholera vibrio will live for 

 considerable periods. Charcoal filters once infected have 

 been repeatedly known to pollute water otherwise pure for 

 many weeks, and cause grave epidemics. 



When, therefore, any town is attacked with or threatened 

 by cholera, special care must be taken to prevent, at all 

 costs, pollution of the public water-supply, and arrange- 

 ments should be made by the sanitary authority for the 

 gratuitous supply of disinfectants, medicine, and food to 

 those in need, and, if possible, to provide due isolation and 

 treatment for persons attacked. All water should be boiled 

 or passed through a Pasteur-Chamberland filter. 



Cholera has been termed a filth-disease, and this title 

 may fairly be applied to it, if we bear in mind that we 

 mean, not that the disease can be generated by filth, but 

 that in filthy surroundings there is the more reason to fear 

 its ravages, and when once it has appeared, it will be 

 expelled with greater difficulty. 



Accumulations of night-soil, rubbish, etc., should be 

 removed, and the places they occupied well cleansed. 

 Uncleanly premises should be thoroughly scrubbed and 

 limewashed, and proper ventilation insisted on. 



Pathogenesis. — The symptoms of Asiatic cholera are 

 intense and sudden fever and collapse, the face being 

 drawn and pinched, and the tongue cold. The urine is 

 suppressed, and the stools have the characteristic rice- 

 water appearance. Death may occur in so short a period 

 as twelve hours after taking the infection, or three hours 

 after the first symptoms are noticed. The incubation 

 period rarely exceeds two or three days. The symptoms 

 differ from those that occur in English cholera only in 

 intensity ; hence we are at present compelled to rely largely 

 on the bacteriological examination to decide whether a given. 



