CHOLERA 211 



is low, and this is in accord with the observations of 

 Pettenkofer that increase in cholera is often preceded by 

 a fall in the ground-water. 



Transmission of the disease may take place by means 

 of water (as at Hamburg), by milk, uncooked vegetables, 

 or by fomites. Like enteric fever, the infection is con- 

 fined to the bowel and stomach discharges ; so that if 

 reasonable care be taken, there is but little fear of the 

 disease being transmitted from the patient to nurses or 

 attendants. 



The ' comma ' is readily capable of a saprophytic exist- 

 ence ; and thus, if cholera-stools were thrown out on to 

 a rubbish-heap without being properly disinfected, the 

 organism might live in such a position for a considerable 

 length of time. If this happens, it is probable that by 

 the action of rain the organisms will find their way into 

 any well near which has its supply from the surface-water ; 

 or should the pollution occur to a stream near the intake 

 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 appKed to it if we bear in mind that we 

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



14—2 



