364 Of the Propagation of Heat 



life consists. But are there not many striking proofs 

 that this is the case in fact ? 



Do not respiration, digestion, and insensible perspiration, all 

 tend evidently (that is to say, according to our assumed 

 principles with regard to the manner in which Heat is 

 propagated in Fluids) to produce and to perpetuate this 

 inequality of Heat in the animal fluids ? And do we 

 not see what an immediate and powerful effect they have 

 in increasing the intensity of the action of the powers 

 of life ? 



If animal life depends essentially on those internal 

 motions in the animal fluids, which, as has been shown, 

 are occasioned by the difference of the specific gravities of 

 their integrant particles, or molecules, arising from their 

 different temperatures, in that case it is evident that 

 the vital powers would be strengthened, or their action 

 increased, either by heat or by cold properly applied. 

 But is not this found to be the case in fact ? Does not 

 the dram of brandy at St. Petersburgh produce the same 

 effects as the draught of iced lemonade at Naples, and by 

 the same mechanical operation, but acting in opposite 

 directions ? And does not the loss of Heat, by insensi- 

 ble perspiration, contribute as efficaciously to the preser- 

 vation of that inequality of temperature which is essential 

 to life, as the introduction of Heat into the system in res- 

 piration ? 



Is not the sudden coagulation of blood, when drawn 

 from a living animal, and are not all the other rapid 

 changes that take place in it, evident proofs of an un- 

 equal distribution of Heat ? And does not the viscosity 

 of blood, as well as its perpetual motions in the vascular 

 system, contribute very powerfully to the preservation 

 of that inequality ? 



