NATURE OF PERSPIRATION. 41 



bonic acid and oily matter also are excreted. It is 

 probable, however, that the composition of the per- 

 spiration varies both at different ages and on differ- 

 ent parts of the skin, as is presumable from the pe- 

 culiarity of odour which it exhales in some situa- 

 tions. The armpits, the groins, the forehead, the 

 hands, and the feet perspire most readily, in conse- 

 quence of their receiving a proportionally larger 

 supply of blood. Every thing tends to show that 

 perspiration is a direct product of a vital process, 

 and not a mere exudation of watery particles 

 through the pores of the skin. 



Taking even the lowest estimate of Lavoisier, we 

 find the skin endowed with the important charge 

 of removing from the system about twenty ounces 

 of waste matter every twenty-four hours ; and when 

 we consider that the quantity not only is great, but 

 is sent forth in so divided a state as to be invisible 

 to the eye, and that the whole of it is given out by 

 the very minute ramifications of the blood-vessels 

 of the skin, we perceive at once why these are so 

 extremely numerous that a pin's point cannot touch 

 any spot without piercing them ; and we see an 

 ample reason why checked perspiration should 

 prove so detrimental to health, because for every 

 twenty-four hours during which such a state con- 

 tinues we must either have twenty ounces of use- 

 less and hurtful matter accumulating in the body, 

 or have some of the other organs of excretion 

 grievously overtasked, which obviously cannot 

 happen without disturbing their regularity and well- 

 being. People know the fact and wonder that it 

 should be so, that cold applied to the skin, or con- 

 tinued exposure in a cold day, often produces a 

 bowel complaint, a severe cold in the chest, or in- 

 flammation of some internal organ ; but were they 

 taught, as they ought to be, the structure and uses 

 of their own bodies, they would rather wonder that 

 it did not always produce one of these effects. 

 PI 



