in Fluids. 363 



After we have patiently examined the result of these 

 investigations, and the imagination has become familiar- 

 ized with the contemplation of the interesting facts 

 they present to it, how much will our ideas be changed 

 with regard to the real state of fluids apparently at rest ! 

 They will then appear to us to be, what no doubt they 

 really are in fact, an assemblage of an infinite number of 

 infinitely small particles of matter moving continually, 

 or without ceasing, and with inconceivable velocities. 



We shall then consider fluidity as the life of Inanimate 

 bodies^ and congelation as the sleep of death ; and we 

 shall cease to ascribe active powers, or exertions of any 

 kind, to dead motionless matter. 



But what shall we think of the vital principle in living 

 animals ? Does not their life also depend on the internal 

 motions in their fluids, occasioned by an unequal distribu- 

 tion of heat ? And is not stimulation, in all cases, the 

 mere mechanical effect of the communication of Heat? 



It is an opinion which we know to be as old as the 

 days of Moses, that the life of an animal resides in its 

 blood ; and it is highly probable that it dates from a period 

 still more remote. It was lately revived by an anatomist 

 and physiologist (now no more), who was eminently dis- 

 tinguished for sagacity ; and it appears to me that the 

 late discoveries respecting the manner in which Heat is 

 propagated in Fluids tend greatly to elucidate the sub- 

 ject, and to give to the hypothesis a high degree of prob- 

 ability. 



According to this hypothesis (as it may now be ex- 

 plained), everything that increases the inequality of the 

 distribution of the Heat in the mass of the blood (even 

 though it should not immediately augment its quantity) 

 ought to increase the intensity of those actions in which 



