374 



EXTERNAL INTEGUMENT. 



organ. It is also very difficult to estimate the quantity of 

 perspiration, especially as it varies greatly under different 

 circumstances : in some cases, as much as from 1 to 100 times. 

 The average quantity of perspiration in '24 hours has, how- 

 ever, been estimated at 1 kil. 300 grams., containing from 15 

 to 20 grams, of solid matter. If the quantity of perspiration 

 is greatly increased the solid excreta increase also, which 

 explains the weakness accompanying long-continued perspi- 



, 



~ 





Fig. 97. Orifices in the su- 

 doriparous glands.* 



Fig. 98. Vertical section of the skin, whose sur- 

 face is represented in the preceding figure. t 



ration. The normal and solid product of the sweat (15 to 

 20 grms.) represents about one quarter of the solid product 

 of urine (60 to 70 grms.); this relation is precisely the same 

 as that which we pointed out between the extent of the two 

 apparatus; it may be generally asserted, that the solid por- 

 tion of glandular products is in proportion to the extent or 

 mass of the glands, and that it is only the amount of water 

 which is variable. 



The perspiration or sweat is composed of water, the ordi- 

 nary salts of the blood, fatty principles, and a large number 

 of acids, such as formic, butyric, and propionic acid, as well 



* Skin of the hand, palmar region. Skin seen from the upper surface, a, 

 Elevation formed by a series of papillae. 6, Interpapillary fissures, c, Sudori- 

 parous pores. (Gurlt.) 



t , Superficial layer of the epidermis, c, Middle layer. <7, Malpighian 

 layer, e, Papilla, /j Dennis. //, Adipose tissue. ', Sudoriparous glands, with 

 tiieir excretory tubes twisted hi a spiral shape at b and y. (Uurlt.) 



