Page:Popular Science Monthly Volume 43.djvu/659

Rh the infection from its previous breeding ground within the body of a previous patient. We now can understand why, when cholera spreads and breaks its bounds, it follows the lines of human traffic and communication. Man, in fact, is the porter by whom the cholera is carried from place to place, and so the rate of diffusion depends upon the rate of travel. But, as no one porter can carry the malady further than he can go between the time of being infected and being struck down, the wide spread of the disease depends not only on the speed of the porter, but on the sanitary condition and social habits of the place where he is taken ill; for, if these are such that he can transfer his load to others, that the infection he deposits can take root and grow in the bodies of fresh patients, some of whom may travel to fresh places and set up fresh foci of disease, the epidemic spreads; but if, from cleanly habits or clean surroundings, or from plentiful supply of pure water, the infection fails to pass from body to body, the malady dies out, and there is an end of the matter. King Cholera is, in truth, a lazy and voluptuous potentate; unless he is carried by quick steamers, he will not travel far without a rest, and when he reaches his destination he declines either to advance or show his power unless he is nourished and pampered with his beloved luxuries of dirt and filth and fecally contaminated water.

The inhabitants of the Indian "endemic area" are a conservative race—the son lives like the father; one generation passes on like another, and centuries of intermittent pestilence and famine have till lately kept down the population to exactly tally with the means of sustenance. The village community has been for ages the unit which, multiplied by thousands, has made up the population. Each village has mostly kept to itself, and, except for the wars of their rulers, the passage of their traders, and their occasional pilgrimages, they have for time immemorial lived an isolated life. At times of pilgrimage, however, all this isolation is cast aside, and pilgrims from widely scattered districts rub shoulders in the bathing places, wash and cleanse their bodies and their clothes in the same water, which in turn they drink in an unsavory fellowship.

Disease may remain for long tied up in a single village; nay, a whole village may die of cholera, and do but little damage to their neighbors; but in times of pilgrimage cholera travels with the pilgrims, and, after the festival is over, is scattered broadcast through the land. Such fairs as that at Hurdwar, at the junction of the hills and plains, outside the endemic area, but attended largely by those who dwell within, have beyond doubt been the great gateways by which cholera has periodically escaped from its confines to ravage the world at large. Of this the historic