Page:Popular Science Monthly Volume 48.djvu/865

Rh was one hundred and fifteen in 1861; the actual deaths have now been reduced to twenty-two, although a much higher figure would be needed to include invaliding. The terrific annual loss of one hundred and forty-eight per thousand in Senegal from 1832 to 1837 is now reduced to about seventy-three. In this last case, however, one hundred and fifty per thousand are returned for sickness every year. A large proportion of these would undoubtedly die if not removed immediately. One may indeed be hopeful from such results that, with further advance in the science of prevention, these figures may be yet further reduced. The system of vacations, of strict regulation of diet, the avoidance of excessive fatigue and exposure, and especially of all forms of agricultural labor, and the extension of the hill-station system, will do much in this respect; so that it is conceded by most candid observers that, with few exceptions, such as Cochin-China and the coast of Africa, robust individuals by great care stand a fair chance of good health in the tropics. Nevertheless, this should never be allowed to conceal the real fact that the English to-day are no nearer true acclimatization in India than they were in 1840. To tolerate a climate is one thing, to become independent of it is quite a different matter. The securing of a permanent footing in the tropics depends upon factors of a totally different nature.

—Passing now from the consideration of the individual to that of the race, the keynote of the matter rests in the much-controverted question of the influence of change of climate upon fertility. For, however well the individual may be enabled, by artificial means or otherwise, to exist, the race will never accommodate itself permanently unless the birth-rate exceeds the death-rate. Here we must first carefully eliminate the effects of ethnic crosses with natives of the tropics; for a fatal mistake of many observers has been the neglect to distinguish the possible sterility induced by intermixtures of race from that caused by a change of climate and of life conditions; or statements of one have been accepted by tyros as equivalent to the other. It has been confidently asserted for so many years that sterility of the white race ensues after three generations in the tropics that it has become a household word in anthropology.