76 THE SKIN. 



does not appear to lose much by the skin, yet the secretion 

 cannot be checked without danger to the animal. Such 

 secretion serves the double purpose of purifying the blood 

 and regulating the temperature of the body. If the skin 

 is covered with an impermeable coating of tar or other ma- 

 terial, death speedily results. The blood becomes poisoned, 

 is unfit to support the functions of the nervous system, 

 acquires a dark colour, and the animal dies as if suffocated. 

 When death occurs under such circumstances, the intestines 

 are found gorged with blood, the lungs congested, heart 

 ecchymosed, air passages full of a frothy bloody liquid, and, 

 in fact, all the lesions exist of an animal destroyed from the 

 effects of a potent blood poison. 



The sebaceous secretion which we find so abundant in the 

 skin of the sheep, is destined to lubricate the surface of the 

 skin and of the hairs. It protects the skins of our domestic 

 quadrupeds from water and from contact with acrid liquids, 

 such as urine, &c. It is characterised by a special odour 

 peculiar to the animal in which it is secreted. 



Esenbeck found that the sebaceous secretion in man 

 contained 



Animal substances .... 358 

 Fatty matters . . . .368 



Phosphate of lime .... 200 

 Carbonate of lime . . . .21 



Carbonate of magnesia . * . /; . 16 

 Chloride of sodium, acetate of soda, &c. : . 37 



1000 



The sebaceous secretion under ordinary circumstances is 

 sufficient to protect the skins of animals, and especially the 

 skins and fleeces of sheep, from the effects of excessive mois- 

 ture. Farmers have, however, found that in wet climates 



