CHAPTER XXXI
HILL DIARRHŒA
Definition.— A form of morning diarrhœa accompanied by flatulent dyspepsia and the passage of copious, liquid, pale, frothy stools. It occurs principally in Europeans on their visiting the hills after residing for some time in the hot lowlands of tropical countries.
Geographical and seasonal distribution. —Crombie, who gave an excellent account of this disease, pointed out that a similar affection may show itself in the highlands of Europe as well as in those of India. It is said also to occur in corresponding circumstances in South Africa and South America. There is no reason, therefore, to suppose that hill diarrhœa is special to India, although, owing to the large European population frequenting the hill sanitaria in that country, it has been particularly noticed there. An elevation of 6,000 feet or over, when combined with an atmosphere saturated with watery vapour, is particularly favourable to its development. In India it is found to begin and end with the rains, during which, in certain years and places, it is apt to assume almost epidemic characters. Thus, during the wet season of 1880, in Simla an epidemic of hill diarrhœa affected from 50 to 75 per cent, of the population, three-fourths of the cases happening within a week of each other. In some years hill diarrhœa is less prevalent than in others; but at the proper season few of the various hill sanitaria of India are without examples.
Etiology and pathology.— It is difficult to say what may be the precise factors determining this disease. The low barometric pressure associated with great elevation above the sea-level may be a favouring circumstance. Damp seems to be indicated by the
