Motion of the Heart and Blood 43 



it by a pipe or artery, or vessel analogous to an artery ;. 

 these are facts which are confirmed by simple ocular 

 inspection, as well as by a division of the vessel, when 

 the blood is seen to be projected by each pulsation of 

 the heart. 



The same thing is also not difficult of demonstration 

 in those animals that have either no more, or, as it 

 were, no more than a single ventricle to the heart, such 

 as toads, frogs, serpents, and lizards, which, although 

 they have lungs in a certain sense, as they have a voice, 

 (and I have many observations by me on the admirable 

 structure of the lungs of these animals, and matters 

 appertaining, which, however, I cannot introduce ire 

 this place,) still their anatomy plainly shows that the 

 blood is transferred in them from the veins to the 

 arteries in the same manner as in higher animals,, 

 viz. by the action of the heart ; the way, in fact, is 

 patent, open, manifest ; there is no difficulty, no room 

 for hesitating about it ; for in them the matter stands 

 precisely as it would in man, were the septum of his 

 heart perforated or removed, or one ventricle made out 

 of two ; and this being the case, I imagine that no one 

 will doubt as to the way by which the blood may pass 

 from the veins into the arteries. 



But as there are actually more animals which have 

 no lungs than there are which be furnished with them, 

 and in like manner a greater number which have only 

 one ventricle than there are which have two, it is open to 

 us to conclude, judging from the mass or multitude of 

 living creatures, that for the major part, and generally,, 

 there is an open way by which the blood is transmitted 

 from the veins through the sinuses or cavities of the 

 heart into the arteries. 



I have, however, cogitating with myself, seen further, 

 that the same thing obtained most obviously in the 

 embryos of those animals that have lungs ; for in the 

 foetus the four vessels belonging to the heart, viz. 

 the vena cava, the vena arteriosa or pulmonary artery,, 



