viii Editor's Introduction 



himself. Their scientific work is therefore of interest, 

 not only for the innate value of the discoveries they 

 made, but also because it shows them as pioneers in 

 that independent spirit of scientific inquiry to which 

 the great advance in natural knowledge since their time 

 is so largely due. 



Harvey's work, by which his name has been made 

 immortal, strikingly illustrates this. He was the first to 

 show the nature of the movements of the heart, and 

 how the blood moved in the body. He did so by 

 putting on one side authority, and directly appealing to 

 observation and experiment. The completeness of the 

 success with which this independent line was taken, as 

 exemplified in his treatise " On the Movement of the 

 Heart and Blood," is such as to excite the admiration of 

 every modern physiologist. " C'est un chef-d'oeuvre," 

 says a distinguished French physiologist, Flourens, " ce 

 petit livre de cent pages est le plus beau livre de la 

 physiologic." l 



The discovery made by Harvey was this : That the 

 blood passed from the heart into the arteries, thence to 

 the veins, by which it was brought back to the heart 

 again ; that the blood moved more or less in a circle, 

 coming back eventually to the point from which it 

 started. In a phrase, there was a Circulation of the 

 Blood. Moreover, this circulation was of a double 

 nature one circle being from the right side of the heart 

 to the left through the lungs, hence called the Pulmon- 

 ary or Lesser Circulation ; the other from the left side 

 of the heart to the right, through the rest of the body, 

 known as the Systemic or Greater Circulation. Further, 

 that it was the peculiar office of the heart to maintain 

 this circulation by its continuous rhythmic beating as 

 long as life lasts. 



This appears very plain and simple to us now so 

 easy that he who runs may read : as important as 



Flourens, Histoire de la Decouverte de la Circulation du Sang, 



1854- 



