ii Circulation of the Blood. 35 



" but it b hem with vehemence when we wake. The 



ve in an opposite manner ; for when we are 

 more swollen, when we are awake they are 

 " shrunken, as anyone may see who watches the veins in the 

 " hands. For when we are asleep the native heat passes from 

 " the arteries by that communication of orifices which we call 

 " anastomosis into the veins and so to the heart. As however 

 " this flowing out of blood to the higher regions, and its return 

 " to lower regions like a Euripus is manifest in sleep and 

 " wakefulness, so also a movement of the same kind is obvious 

 " in every part of the body to which a ligature is applied, or 

 " where the veins are blocked in any other way. For when its 

 " free channel is obstructed, a stream swells at the point to- 

 i( wards which it is accustomed to flow. The blood then rushes 

 " forcibly back to its source, lest, being cut off, it should be 

 " extinguished." 



We must therefore admit that CsBsalpinus had not only 

 clearly grasped the pulmonary circulation, but had also laid 

 hold of the systemic circulation ; he recognized that the flow of 

 blood to the tissues took place by the arteries and by the 

 arteries alone, and that the return of the blood from the 

 tissues took place by the veins and not by the arteries. 



In respect to these important points, he had obviously 

 freed himself from the Galenic doctrine. But the question 

 may fairly be asked, How far were these views the outcome 

 of patient research, of real study of the phenomena themselves? 

 How far were they flung out in the spirit of controversy 

 as effective assaults lipon accepted doctrines ? 



We may feel inclined to take the latter view when we 

 notice how little acceptance Csesalpinus's new doctrines met 

 with among his contemporaries; how little heed indeed was 

 paid to them until they were disinterred, so to speak, by 

 antiquarian research, and in particular what little influence 

 they seemed to have exerted upon Csesalpinus's great con- 

 temporary who made the next great step in the advance of the 

 true theory of the circulation, I mean Hieronymus Fabricius, 

 often spoken of, from the place of his birth, as ab Aquapendente. 



Born, in 1537, of humble parents, in the little Tuscan town 



3—2 



