HARVEY AND THE CIRCULATION. 239 



course of the fourth or fifth day of the incubation, in the guise of 

 a little cloud, the shell having been removed and the egg im- 

 mersed in clear tepid water. In the midst of the cloudlet in 

 question there was a bloody point so small that it disappeared 

 during the contraction and escaped the sight, but in the relaxa- 

 tion it re-appeared again, red and like the point of a pin, so that 

 betwixt the visible and invisible, it gave by its pulses a kind of 

 representation of the commencement of life." 



Harvey describes the motion, action and office of 

 the heart in as clear a manner as any physiologist can 

 do it to-day, showing that so far as the general circu- 

 lation is concerned, he thoroughly understood what he 

 claimed to understand: 



" The auricle contracts, and in the course of its contraction, 

 throws the blood into the ventricle, which being filled the heart 

 raises itself straightway, makes all its fibers tense, contracts the 

 ventricle, and performs a beat, by which beat it imnlediately 

 sends the blood supplied to it by the auricle into the arteries ; the 

 right ventricle sending its charge into the lungs by the vessel 

 which is called vena arteriosa (pulmonary artery), but which, in 

 structure and function, and all things else, is an artery ; the left 

 ventricle sending its charge into the aorta, and through this by 

 the arteries to the body at large. 



"These two motions, one of the auricles, another of the ven- 

 tricles, take place consecutively, but in such a manner that there 

 is a kind of harmony or rhythm preserved between themj the two- 

 concurring in such wise that but one motion is apparent, espe- 

 cially in the warm blooded animals in which the movements in 

 question are rapid. Nor is this for any other reason than it is in 

 a piece of machinery in which, though one wheel gives motion to 

 another, yet all the wheels seem to move simultaneously ; or in 

 that mechanical contrivance which is adapted to firearms, where 

 the trigger being touched, down comes the flint and elicts a spark, 

 which falling among the powder, it is ignited, upon which the 

 flame extends, enters the barrel, causes the explosion, propels the 

 ball, and the mark is attained all of which incidents, by reason 

 of the celerity with which they happen, seem to take place in the 

 twinkling of an eye." 



Harvey says that in the heart there are four mo- 



