ANIMAL HEAT. 



lor 



a torpid state for months together, when the function of 

 respiration is wholly suspended, and still their tempera- 

 ture is above that of the surrounding medium. Some 

 late experiments of Mr. Brodie seem to show that the 

 production of animal heat is entirely independent of res- 

 piration. He inflated the lungs of an animal after death 

 and maintained an artificial respiration. The usual 

 changes continued to be wrought on the blood ; it was 

 converted from its modena hue to bright scarlet, and 

 carbonic acid was formed, but the body lost its heat as 

 fast as if it had been suffered to remain at rest. 



Emily. But, Dr. B., are we to give up the point in 

 despair and consider it wholly beyond our power of ex- 

 planation ? 



Dr. B. It has been lately suggested that it might be 

 the result of a peculiar action of the nervous system on 

 the capillary vessels ; but no attempt having been made 

 to establish it by a systematic array of proofs and argu- 

 ments, it is as yet merely a suggestion. 



Emily. If you had not objected to my analogy 

 drawn from the vegetable kingdom, I should say that 

 this theory was equally unsupported by it, for I never as 

 yet heard that plants possess a nervous system. 



Dr. B. They have not a nervous system it is true, 

 but for any thing we know, particles of nervous matter 

 may be diffused through their structure, and capable of 

 producing the same effects in regard to vegetable heat, 

 that a proper nervous system does in regard to animal 

 heat. But although we are unable to explain the cause 

 of this phenomena, the facts connected with it are no 

 less certain, or interesting. Some of them are as curi- 

 ous as they are inexplicable, particularly the power of 

 organized bodies to preserve a uniform temperature not- 

 withstanding the changes in the surrounding medium. 

 Thus the temperature of the human body is between 

 98 and 99 of Far. whether we examine it in the Esqui- 

 maux who dwells in his icy hut under the polar circle, 

 or the Negro who feels the scorching rays of an equato- 

 rial sun. 



