Page:Popular Science Monthly Volume 48.djvu/739

Rh of which the Japanese share to some extent. Their liability to consumption seems to be akin to that penchant for alcoholism, which is lacking among the Chinese because of the national opium habit.

The negro even in the tropics is especially subject to all affections of the lungs, a fact which constitutes a serious bar to his wide extension over what has been designated by Dr. Fuchs the catarrhal zone, in contradistinction to the dysenteric zone of the tropics. The black races have in general less fully developed chests and less respiratory power than the European race. They perspire less freely, and their skin is thicker, or at least more dense, so that oxygenation by the lungs alone is more necessary. They are consequently exceedingly sensitive to atmospheric changes, and are severely handicapped in any migration for this reason. Almost invariably, where the European succumbs to bilious or intestinal disorders, the negro falls a victim to diseases of the lungs even in the tropics. An interesting case is instanced of a caravan in Senegal, composed of ninety-five negroes and ninety Europeans, in which the average mortality for each of the two contingents was exactly equal for two years. Yet only one of the whites was affected with disease of the lungs, while five of the eleven negroes who died succumbed to diseases of this class. Similar to the effect of change of climate upon the negro in inducing respiratory derangement is the influence exerted by altitude, which will be discussed in another place.

Dr. Ashmead has suggested an interesting reason for the predisposition of the negro for consumption—namely, that the broad, open nostril of the race is unfitted to perform the necessary service of warming the air before its entrance into the lungs. Leptorrhinism, he asserts, is due to natural selection, which has fixed upon that form of nose as most suitable to the temperate zone; and the negro, deprived of this advantage, suffers from disease of the