Page:Popular Science Monthly Volume 48.djvu/864

782 appears that the first effects of a sojourn in the tropics is to induce symptoms which point toward the peculiarities of the native type. Thus the increase in the size of the liver indicates the operation of those causes which have finally made the negro's liver normally larger than that of the European. The only present difficulty is that an unusual strain is suddenly put upon the various organs in this process of gradual adaptation which is often too severe; as, for example, the high mortality among Europeans from derangement of the liver, such as hepatitis, bilious fever, abscesses, and the like, which indicates that some physiological change has taken place which has entailed an excessive demand upon the activities of this organ. Similarly the extreme liability of the negro to disases of the lungs in the temperate zone may be due to his lack of physiological accommodation to those circumstances which have in hundreds of generations produced the European type. To expect that man can in a single generation compass the ends which Nature takes an age to perform is the height of folly. The exact nature of the physiological processes induced by the tropics is, however, so imperfectly known that we must in general rely upon concrete experience for our further conclusions.

—Hygiene and sanitation have accomplished wonderful results in assisting the individual to withstand those immediate effects of climatic change which, as we have said, are so often fatal. The yearly loss at one time in India was eighty for each regiment of one thousand men. In 1856 it had been reduced to sixty-nine; from 1870 to 1879 it ranged about sixty-two; and in 1888 the annual loss was only fifty, including deaths and invaliding. The loss in Cochin-China per regiment