CHOLERA. l8l 



to be endemic, but on account of some local circumstances 

 connected with temperature and vegetation it is developed 

 only in crops at harvest time, as it were. In the third case, 

 in the Nile delta, the disease is extremely intermittent in its 

 outbreak, and occurs only in those years in which the condi- 

 tions as regards temperature, moisture, &c., are specially 

 favourable for its development. In connection with local 

 peculiarities as favouring the growth of the bacillus and the 

 spread of the cholera, Macleod makes several very interesting 

 observations, some of which bear out in a most remarkable 

 manner Koch's statement as to the general laws that 

 govern the spread of the disease, and also as to the minor 

 local factors that determine individual outbreaks. The 

 population in Shanghai he divides into three classes : resident 

 foreigners, amongst whom deaths from cholera average less 

 than 2 per 3000 per annum ; amongst the seafaring foreign 

 population the average is very much higher, as of the sailors 

 who come to port there die from cholera from 1 5 to 30 per 

 i ooo yearly ; whilst among the Chinese, even in the settlement, 

 there are rarely fewer than from 200 to 300 deaths in a single 

 season. What part then do local peculiarities and customs play 

 amongst these three sets of people ? It is a fact, generally 

 recognized, that any disturbance of the digestive function is 

 the principal predisposing cause of the disease in a cholera 

 outbreak a fact that is explained by the absence of the 

 ordinary amount of acid from the gastric juice in these 

 cases ; such gastric derangement is specially met with after a 

 bout of drinking. Macleod says, " Among the sailors a night 

 ashore is the usual precursor of the disease, and commonly 

 that indicates a large consumption of liquor." This, how- 

 ever, does not account for all the cases that occur, and he 

 says, " Occasionally men who have not been ashore are 

 attacked. A sailor belonging to an American ship was 

 attacked two or three days after arrival ; he had not been 

 ashore, the ship had touched at no port for weeks before, and 

 the water supplied on board had been in use during the 

 voyage. The captain reported that he had specially en- 

 couraged the men to eat fresh vegetables largely, and that 

 he had seen the man referred to sitting on deck munching 

 lettuce the day before he became ill (three of this ship's 

 crew died of cholera). These vegetables had been supplied 

 by Chinese bumboats." 



