FIRST ORDINARY MEETING. 17 
matter light, the tint of the skin will be much affected by any 
change in the supply of blood to the capillaries at the surface of the 
body. This is the reason why the whites alone can turn pale and 
blush. 
Closely related to the pigment of the skin are the colouring matters 
of the eye and hair. Dark-skinned people usually have black eyes 
and hair; fair hair and blue eyes are seldom found except in con- 
junction with a fair skin ; and the eyes and hair of albinoes, in whom 
the pigment of the skin is wanting, are likewise destitute of colouring 
matter. The pink hue of their eyes is due to minute blood-vessels, 
whose colour is masked in ordinary organs by the pigment of the iris. 
It is noteworthy that the colouring matters of the epidermis and 
the iris serve a very important purpose ; they protect the tender un- 
derlying parts from the injurious effects of too much heat and light. 
Albinoes everywhere find it necessary to protect their skins and eyes 
from the action of the sun’s rays. In warm countries they seldom go 
outexcept at night. There is this difference between them and other 
men, that long-continued exposure to the sun, which ordinarily 
develops a condition of the skin capable of resisting its rays, does not 
do so in their case. It may here be remarked that, the greater the 
quantity of the pigment, the less transparent will the epidermis be, 
and the more effective will it be as a protective agency. On the con- 
trary, the smaller the quantity, the greater the transparency, and the 
less the protection. 
Under certain circumstances the exposed parts of our bodies 
become tanned, that is to say, an increase in the colouring matter 
which they contain takes place. Dark whites tan brown, fair whites 
tan red. The change is caused by the influence of the sun or wind, 
and is obviously protective in its character, as the unpleasant feelings 
which result from the first exposure do not recur when we have 
become thoroughly tanned. This fact, I believe, contains the key 
which explains the distribution of colour among the races. The 
climate, or the mode of existence of most races, renders it an 
advantage to them to begin life more or less deeply tanned. 
As an excretory organ, it is the function of the skin to discharge 
water, carbonic acid and urea—the first in large, the others in small 
quantities. Perspiration, or the excreting of water with some saline 
matter in solution, is effected in two ways. In the first place, 
sudoriparous glands, imbedded in the true skin, secrete sweat from, 
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