THE SWEATING APPARATUS 



Tropical Races Are Provided with More Sweat Glands Than Are the White 



Races of Northern Climates — Valuable Adaption Brought 



About by Evolution 



IN THE course of evolution the be permanent. But if there are no 



races of the tropics must have unchangeable differences of this sort: 



become different from the northern if it is merely a question of proper 



races in many ways. Skin color is clothing and diet and knowing how to 



the most conspicuous one. Differences care for the health, the white races 



in disease resistance are of great import- might be able to spread over a great 



ance. It has further been suggested deal of fertile territory outside of the 



that the tropical peoples have a more temperate zone. 



effective mechanism for regulating the The late Lieut. Col. Chas. E. Wood- 

 internal heat of the body than have the ruff brought together a great deal of 

 residents of cooler climes. evidence to show that the light skin 



The bod}^ temperature is partly kept of the white race is an almost fatal 



down through the evaporation of sweat handicap in v/arm climates. The Philip- 



from its surface, and it has been said pine students proposed to investigate 



that the sweat glands of the tropical as man}^ similar characters as possible, 



races are larger and more numerous than and Clark and Lhamon undertook the 



those of northerners. It has also been study of sweat glands. They have 



alleged that they work in a different recently published a preliminary report^ 



way: "According to Aron, the Negrito which shows that the alleged differences 



secretes small beads of sweat over the do exist, and that they are of consider- 



entire body, which soon forms a thin able extent. 



film. As the whole surface of the body A count of more than a quarter of a 



is covered by this water film, the maxi- million sweat glands in individuals of 



mum cooling effect from evaporation is different races has shown them that 



attained. In the case of the white there is much variation in size in an 



man, on the other hand, the sweating is individual. Those on the palm of the 



practically limited to certain areas of hand and the sole of the foot are the 



the body surface. In these areas the most constant in size, and also appear 



sweating may be quite profuse, but as first in the embryo. It seems probable 



most of it drops off, comparatively little that the glands on those two surfaces 



cooling effect from evaporation is are more useful to moisten the skin and 



produced." prevent slipjjing than they are to 



When American men of science be- reduce body temperature, 



came established in the Philippines, The following table shows the average 



one of the investigations they under- nimiber of glands per square centimeter 



took was to get tnore definite evidence of skin area on the fingers of men of 



about the differences in adaptation of various races : 



various races to life in the tropics. American (white) 558 



This is not merely a matter of academic American (negro) 597 



interest; if certain adaptations are Filipino . . ~ 653 



necessary to enable a race to live in the Moro 68-1 



tropics, and if the white race lacks these Negrito (adult) 709 



adaptations, it is evident that tropical Hindu (vSikh?) 738 



colonization by the white race will never Negrito (youth) 950 



1 Observations on the sweat glands of tropical and northern races. By Elbert Clark and 



Rushkin H. Lhamon, Department of Anatomv, University of Chicago, Anat. Rec, xn, pp. 13;- 

 1-49, February, 1917. 



221 



