The Skin. 193 



As epidermis largely contains sulphur, this is one channel 

 of removing it from the body. 



By means of the glands in the skin we find secreted an 

 albuminous fluid termed ' sweat,' and a fatty material 

 known as 'sebum.' 



Sweat, or perspiration, is not found to occur over the 

 general surface of the body in any other hairy animal than 

 the horse. It is said that sheep perspire (?), the ox to a less 

 extent and principally on the muzzle, and the dog and cat 

 on the foot-pads. 



The sweat exists in two forms : viz., the invisible vapour 

 which is always rising from the surface of the skin, and 

 distinguished as the 'insensible perspiration '; and the visible 

 material, which is termed ' sweat.' 



Colin gives various figures representing the insensible 

 perspiration, from which we gather that 11 lbs. of water 

 probably represents this loss in the horse for 21 hours. 

 Much depends upon the humidity of the atmosphere : the 

 drier it is the greater the insensible perspiration. 



Sweat obtained from the horse by scraping is always 

 alkaline — strongly so ; after filtration it is the colour of 

 sherry, and possesses a peculiar horse-like odour, with a 

 specific gravity of 1020. One specimen examined by me 

 gave the following analysis :* 

 Water - - 94-3776 



The proteids are thus seen to be serums albumin and 

 globulin, and their constant presence has been determined 

 by a number of observations. The mineral matter is very 



* Journal of Physk>logy,vo\. xi., No. 6. 



13 



