MOTION OF THE HEART AND BLOOD 



birth in man, and in certain animals, but even for 

 many months in others, as anatomists have noted, 

 and for years or life in still others, as in the goose, 

 snipe, and many birds and small animals. This per- 

 haps persuaded Botallus^ that he had found a new 

 passage for blood from the vena cava to the left 

 ventricle. I confess I almost thought so myself when 

 I first saw the condition in larger adult mice. 



From this it appears that the same thing happens 

 in human and other embryos in which these junctions 

 are not closed: the heart, in its beat, forces the blood 

 through the wide open passages from the vena cava 

 to the aorta through the two ventricles. The right 

 ventricle, receiving blood from its auricle, propels it 

 through the pulmonary artery and its continuation, 

 called the ductus arteriosus, to the aorta. At the 

 same time the left ventricle contracts and sends into 

 the aorta the blood, which, received from the beat of 

 its auricle, has come through the foramen ovale from 

 the vena cava. 



In embryos, then, while the lungs are as inert and 

 motionless as though not present, Nature uses for 

 transmitting blood the two ventricles of the heart as 

 if they were one. The situation is the same in embryos 



^ L. Bottallus, a French anatomist of little ability, was born about 

 1530. "His very imperfect description of the ductus arteriosus^ which 

 we know now to be due to the persistence of the fifth cephalic aortic 

 arch on the left side, appeared in 1565. To call the structure ductus 

 Botalli is an anachronism, as it was in fact well known to Galen." 

 (C. Singer, The Evolutuon of Anatomy, New York 1925.) With what 

 skill and precision Harvey describes the fetal circulation! 



[57] 



