HARVEY AND EXPERIMENTAL OBSERVATION 49 



ebb and flow. In reference to the anatomy of the blood- 

 vessels, he goes so far as to say of the portal vein and the 

 vena cava in the liver that " the extreme ramifications of these 

 veins inosculate with each other, and in many places appear 













FIG. ii. Scheme of the Portal Circulation According 



to Vesalius, 1543- 



to unite and be continuous." All who followed him had the 

 advantage of his drawings showing the parallel arrangement 

 of arteries and veins, and their close approach to each other 

 in their minute terminal twigs, but no one before Harvey 



