28 CIRCULATION OF THE BLOOD 



however, am in great doubt as to the office of the heart 

 in this part." 



He further sets forth his whole policy with reference to 

 Galen's view in the following interesting passage : ' In 

 considering the structure of the heart and the use of its 

 parts, I have brought my words for the most part into 

 agreement with the teachings of Galen : not because I 

 thought that these were on every point in harmony with 

 the truth, but because, in referring now and again to a new 

 use and purpose for the parts, I still distrust myself. 

 Not long ago I would not have dared to turn aside even a 

 nail's breadth from the opinion of Galen, the prince of 

 physicians. . . . But the septum of the heart is as thick, 

 dense, and compact as the rest of the heart. I do not, 

 therefore, know ... in what way even the smallest 

 particle can be transferred from the right to the left 

 ventricle through the substance of that septum. . . . 

 When these and other facts are considered, many points 

 concerning the arteries come forward about which doubts 

 may reasonably arise. We may note too that almost no 

 vein goes to ventricle, intestines, or spleen without an 

 accompanying artery, and likewise the portal vein has an 

 accompanying artery almost throughout its course." 



