viil INTRODUCTORY REMARKS. 



founded upon this grand principle --Me circulation. 

 It has not yet explained the epicycles, as I may 

 be allowed to call the partial systems, and various 

 relations of parts, both fluid and solid, on which 

 the anomalies of the body, the nature of diseases, 

 and the operations of medicines must depend. Had 

 Newton only discovered the general operation of 

 gravity upon all matters, and barely hinted that the 

 motion of the planets must depend upon it, philoso- 

 phers had then understood the system of the world 

 nearly as well as we do now the system of the 

 body." * 



A conviction of the truth of the opinions ex- 

 pressed in the preceding quotations, led me, many 

 years since, to engage in an attempt to elucidate 

 some points in the physiology of the circulation of 

 the blood, and to apply that great principle more 

 extensively to the illustration and explanation of 

 pathological phenomena. For, since all experience 

 shows us that the incessant and regular motion of 

 the blood is, in the human body, the source and 

 supporter of those secondary functions which col- 

 lectively constitute Animal Life, it seems but 

 natural to seek in its irregularities and disorders for 



* An Epistle to the Rev. Dr. Hales, introductory tu ;in Ks-say on 

 the Blood. By Richanl Duvie.-. M.I). U:ith. r 



