DIFFERENT OPINIONS. 535 



But it is now certain that such injuries, like 

 the influence of narcotic poisons, diminish or 

 destroy the function of respiration ; and it has 

 been proved by the experiments of Hastings, 

 Holland, Flourens, and many others, that the re- 

 duction of temperature may be greatly retarded 

 by artificial inflation of the lungs after decapi- 

 tation, and division of the 8th pair of nerves. 



Others maintain, with Dr. Philip, that animal 

 heat is the result of secretion ; while Tiedmann 

 contends that its evolution is " a vital act, which 

 depends immediately on the process of nutrition, 

 the conditional and preservative cause of life." 

 (Compar. Physiology, p. 247.) Mr. Mayo says, 

 that physiologists at present incline to the opinion 

 that "the production of animal heat depends on 

 nervous influence ;" but without explaining how 

 and whence the nervous system obtains it : and 

 he adds in another page, that " the source of vital 

 heat is unknown." (Physiology, pp. 79, 264.) 



With Dulong and Despretz, Dr. S. Smith re- 

 gards respiration as the principal source of animal 

 temperature, but thinks there is reason to believe 

 that the remainder is extricated from the blood 

 by nervous influence, as in the processes of se- 

 cretion and nutrition. (Philosophy of Health, vol. 

 ii. p. 153.) Chaussat concludes, from his own 

 experiments, that the evolution of heat depends 

 more on the cervical portion of the spinal marrow 

 or medulla oblongata, than on the brain. (Ann. 



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