AN ANATOMICAL STUDY ON THE 



the heart, which plainly transmits it by a tube 

 analogous to an artery. This may be confirmed by 

 inspection, or section of the artery, the blood spurting 

 with each beat of the heart. 



It is not hard to see the same thing in other animals 

 with but a single ventricle, as toads, frogs, serpents 

 and lizzards. They have lungs of a sort, as a voice. 

 I have made notes on the excellent structure of their 

 lungs, but they are not appropriate here. It is 

 obvious in opening these animals that the blood is 

 transferred from the veins to the arteries by the 

 heart beat. The way is wide open; there is no dif- 

 ficulty or hesitancy about it; it is the same as it would 

 be in man were the septum of the heart perforated or 

 removed, making one ventricle of the two. Were this 

 so, no one would doubt, I think, how blood passes 

 from veins to arteries. 



Since there really are more animals without lungs 

 than with them, and also more with a single ventricle 

 in the heart than with two, it may be concluded that 

 for the majority of animals, an open way exists for 

 blood to pass through the cavity of the heart from 

 the veins to the arteries. 



I have perceived further that the same thing is 

 very apparent in the embryos of animals possessing 

 lungs. 



It is well known by all anatomists that the four 

 blood vessels belonging to the heart, the vena cava, 

 pulmonary artery, pulmonary vein, and aorta, are 

 connected differently in the fetus than in the adult. 



I 54] 



