PHYSIOLOGY OF THE CIRCULATION. 1*23 



distributed throughout the rest of the system receive 

 carbonic acid; which, with that generated in the 

 mass of blood itself, escapes from the exhalant vessels 

 of the lungs. 



Physiologists and natural philosophers have long 

 supposed that many of the purposes served in the 

 animal economy by the circulation of the blood are 

 accomplished by the operation of ordinary hydro- 

 dynamic principles. 



In the preceding remarks I have endeavoured, 

 through the medium of those principles, to establish 

 an intimate connection between certain important 

 functions in animals and the great discovery of 

 Harvey, viz., the incessant motion of the blood. In 

 the course of this attempt I may occasionally appear 

 to have diverged somewhat from my more immediate 

 subject ; but these slight digressions, if they should 

 be considered such, may perhaps be pardoned, inas- 

 much as they constitute an imperfection Avhich must 

 be common to all who seek for a solution of the 

 mysteries of organic life in the simpler, and uot less 

 beautiful, laws of inanimate matter. 



