22 THE LAWS OF ORGANIC 



great care and exactness on the part of the ope- 

 rator, to enable him to draw legitimate conclu- 

 sions ; indeed, from their delicate nature, they 

 are liable to several sources of error. The re* 

 suits of his experiments are not uniform, but 

 the greater number seem to shew that less oxy- 

 gen is consumed when the animal is constrain- 

 ed. " It was found, however, that, in certain 

 cases, the cooling was more rapid than ordinary, 

 even when more oxygen is consumed, owing (as 

 the author conjectures,) to the struggles which 

 are made carrying off a portion of the heat."* 



It is possible, when an animal is placed in these 

 circumstances, that less oxygen may disappear, 

 but this is not the cause of the phenomena ; these 

 will be explained by referring them to a more 

 general and important principle, viz. the charac- 

 ter of the respiration and the consequent con- 

 dition of the circulation. When an animal is 

 put upon its back, the palpitation of the heart 

 is perceived, and the state of the breathing is 

 extremely hurried, from mental influence. The 

 troubled action of the heart shews it is oppress- 

 ed by the quantity of blood which is determined 

 to the lungs, occasioned by the deep inspiratory 

 acts of respiration ; and these possessing more 

 than they are accustomed to present to the 

 agency of the air, it therefore follows that the 



* BOSTOCK'S Elementary System of Physiology, Vol. if. 

 p. 273. 



