AND ANIMAL LIFE. 117 



CXX. The influence of warmth in animals ope- 

 rates upon the surface of the body and the or- 

 gans which are fitted to improve the qualities of 

 the blood. By exciting the surface, the action 

 of the capillaries is universally stimulated ; and 

 the consequence of this is, that the internal or- 

 gans participate in the change, as they are neces- 

 sarily relieved of a portion of blood, from its more 

 equal diffusion, and are rendered more capable of 

 oxygenating, transmitting, and assimilating that 

 which they receive. By acting upon the lungs, a 

 direct stimulus is applied to their capillary ves- 

 sels, which are intimately concerned in effecting 

 the various changes of the blood, and directing the 

 mode of its distribution ; and in so far as these are 

 accomplished, the effects arising from the external 

 cause will be more or less permanently or generally 

 established. If these alterations have taken place, 

 it must be allowed that the nervous system will 

 soon evince a corresponding condition, as the re- 

 sult of these alterations ; and we observe, that 

 whatever depends on motion or sensation, becomes 

 unusually energetic. 



CXXI. Suppose a plant and an animal to have 

 been brought prematurely forward, and after- 

 wards to be exposed to a degree of cold rather 

 severe for the season, they are both influenced 

 in the same way by the same exciting and proxi- 

 mate causes. The surface of both is highly vas- 

 cular ; and as a greater proportional quantity of 



