(jeneial Principles of Pht/siologi/. 275 



the same proportion rises. When there is a natural defect in 

 the organs of circulation, and particularly when this defect is 

 such as prevents the blood passing through the lungs, with the 

 freedom necessary to its healthy state, the temperature is found 

 below the natural standard. The reader may consult a paper 

 on this subject, by Mr. Earle, in the seventh volume of the 

 Transactions of the Medico-Chirurgical Society, in which there 

 are many excellent observations. As we proceed, we shall find 

 proofs founded on direct experiments, that the temperature de- 

 pends on the state of the circulation, and particularly on the 

 passage of the blood through the lungs, which to detail here, 

 would too much anticipate some of the other parts of the 

 subject. 



Whether caloric be a substance, or as some of the first che- 

 mists of our time are inclined to believe, only a certain motion 

 of the particles of bodies, it is of course foreign to this paper to 

 inquire ; but it appears from the foregoing observations, and 

 will, I think, appear still more 'strikingly from those I shall have 

 occasion to add, that the maintenance of animal temperature 

 must be ranked among the results of the action of the nervous 

 system on the blood. It is on this account that I have else- 

 where said, that if caloric be regarded as a substance, its evolu- 

 tion in the animal body must be ranked with the secreting pro- 

 cesses; the definition of secretion, I conceive, being the evolu- 

 tion of a terlium quid, in consequence of that action. 



When to the functions which have now been detailed, we 

 add, that the nerves are the means of conveying impressions to 

 and from the sensorium, we have, I believe, enumerated the 

 whole of the functions of the nervous system properly so called. 



Although it has been very generally admitted, that the 

 nerves of the organs of sense perform no other function but that 

 of conveying to the more central parts of the nervous system 

 the impressions they receive, it has been supposed that the 

 nerves of other parts, and particularly those of the viscera, are 

 capable of so impressing each other, that these parts sympathize 

 independently of the more central parts of the system. This 

 position, which, were it correct, would seem in opposition to 



