PERSPIRATION. 



Sweat-gland and part of its duct. a. Venous 

 radicle. &. Capillary plexus separated from 

 the gland, and rising from arteries which also 

 anastomose. 



with a saltish taste and more or Fi g- 138 - 



less intense odor, and generally 



presenting a weak acid reaction. 



The sweat from the axillae and the 



feet is, however, often found to be 



alkaline. 



There are no morphological ele- 

 ments in sweat, except the scaly 

 epithelial cells of the skin, which 

 are accidentally present. 



The solid constituents of sweat 

 probably do not exceed 1.25 per 

 cent.; Favre says .443 per cent, 

 only. Of the solid constituents, 

 chloride of sodium is the most 

 abundant. . The salts of ammonia 

 are also present in it. Earthy phosphates and a little peroxide of 

 iron are also present, but these are probably derived from the epi- 

 thelial cells in the fluid. 



Thefqt in the sweat may probably be, in great part, derived from 

 the sebaceous follicles. But Krause has found that the sweat-glands 

 also secrete fat, to some extent. Lehmann has proved that it con- 

 tains butyric acid. 



Sweat also contains the acetic and formic acids (Schottiri), and the 

 lactic (Favre), and a sulphurous matter (Lehmann). Urea is also a 

 normal constituent. (Favre.) The thin bluish layer sometimes found 

 on the bodies of persons who have died of cholera is a fine powder, 

 composed, for the most part, of urea. Certain pigments sometimes 

 occur in sweat, especially that of the bile in cases of icterus. 



It has also been demonstrated that gases, especially carbonic acid 

 and nitrogen, are given off in the liquid secretion of the sudoripa- 

 rous glands, and these must not be overlooked in determining the 

 functions of the skin. The carbonic acid predominates in case of 

 a vegetable, and the nitrogen of an animal, diet. But less gas is, on 

 the whole, given off when the perspiration is active, as after brisk 

 exercise. 



The amount of perspiration, in twenty-four hours, averages, in 

 case of an adult man, not far from 25 J ounces. ( Valentin.) Krause 

 calculated 25 T 7 g ounces of water, J ounce of organic and volatile 



