THE CIRCULATION OF THE BLOOD 447 



further found that, in the arteries, the blood, as had pre- 

 viously been known, was travelling from the greater trunks 

 towards the ramifications. Moreover, referring to the ideas 

 of Columbus and of 

 Galen (for he was 

 a great student 

 of literature, and 

 did justice to all 

 his predecessors), 

 Harvey accepts and 

 strengthens their 

 view of the course 

 of the blood through 

 the lungs, and he 

 shows how it fitted 

 into his general 

 scheme. If you will 

 follow the course of 

 the arrows in Fig. 4 

 you will see at once 

 that in accordance 

 with the views of 

 Columbus the 

 blood passes from 

 the right side of the 

 heart, through the 

 lungs, to the left 

 side. Then, adds 

 Harvey, with abun- 

 dant proof, it passes 

 through the arteries 

 to all parts of the 

 body ; and then, at 

 the extremities of 

 their branches in the 

 different parts of the 

 body, it passes (in 

 what way he could 

 not tell, for his. 

 means of investiga- 

 tion did not allow 



him to say) into the roots of the veins then from the roots 

 of the veins it goes into the trunk veins then to the right 

 side of the heart and then to the lungs, and so on. 



FIG. 4. The circulation of the blood 

 demonstrated by Harvey (A.D. 1628). 



