AND ANIMAL LIFE. 133 



cooling, are easily explained by the present prin- 

 ciple, we shall now pass to several others brought 

 forward by Dr EDWARDS, not in support of his 

 own opinion, but as facts. He states that exte- 

 rior heat supplies the deficiency in the faculty of 

 producing* 



When we apply warmth to the surface of the 

 body, without in the least modifying the tempe- 

 rature of the air we inspire, we augment the ge- 

 neration of animal heat. This effect is not easily 

 perceived when the system is naturally excited, 

 because the difference we can produce in the 

 mode of circulation is too slight to influence, in 

 an appreciable manner, the generation of this 

 principle : but if this be employed when the 

 powers of life are much oppressed by a great de- 

 termination of blood to the internal cavities, 

 the beneficial influence of this agent is strikingly 

 displayed. Physiologists and physicians have 

 long known that such means diminish internal 

 congestion ; but they must have supposed that 

 this was confined chiefly to the abdominal vis- 

 cera, as they appear unacquainted with the ge- 

 neral principles and their application, fully treat- 

 ed of in various parts of this work. Friction, ap- 

 plied to the body, produces similar consequences 

 to those of heat ; and this shows that the action 

 of heat affects the internal production principally 

 by bringing to the surface an additional quantity 



* Dr Ei> WARDS, p. 480. op. citat. 



