AN ANATOMICAL STUDY ON THE 



to fit exactly, in others poorly and negligently, so that 

 they may be closed according to the greater or lesser 

 impulse from the contraction of the ventricles. In 

 the left ventricle, therefore, that the closure may be 

 made more complete against the stronger impulse, 

 there are only two, placed like a miter, and length- 

 ened in a conical form so they may come together 

 medianly and close very exactly. This probably led 

 Aristotle to consider this ventricle double, divided 

 transversely. Likewise, that blood may not escape 

 back into the pulmonary vein and thus reduce the 

 power of the left ventricle to pump blood through the 

 whole body, these mitral valves surpass in size, 

 strength, and exactness of closure those placed in the 

 right ventricle. Hence, necessarily, no heart can be 

 found without a ventricle since there must be a source 

 and store-house for blood. 



The same does not always hold for the brain.' 

 Almost no kind of bird has a ventricle in the brain, as 

 is clear in the goose and swan, whose brains nearly 

 equal in size that of the rabbit. But the rabbit has 

 ventricles in the brain while the goose does not. 



Wherever there is a single ventricle in the heart, a 

 flaccid, membranous, hollow, blood-filled auricle is 

 appended. Where two ventricles exist, there are like- 



' This paragraph and the last sentence of the preceding seem to 

 be unnecessary appendages to the argument. They appear in the 

 middle of a long paragraph which has been broken up for greater 

 ease in reading. Was Harvey implying that there is no necessary 

 store-house for "animal spirits" in the brain as there is for "vital- 

 spirits" (or blood) in the heart.'' 



[122] 



