Heart and Blood 107 



fever ; in like manner, on compressing the ringers in 

 youthful and delicate subjects during a feeble paroxysm, 

 I have readily perceived the pulse there. On the other 

 hand, when the heart pulsates more languidly, it is 

 often impossible to feel the pulse not merely in the 

 fingers, but at the wrist, and even at the temple ; this 

 is the case in persons afflicted with lipothymiae and 

 asphyxia, and hysterical symptoms, as also in persons 

 of very weak constitution and in the moribund. 



And here surgeons are to be advised that, when the 

 blood escapes with force in the amputation of limbs, in 

 the removal of tumours, and in wounds, it constantly 

 comes from an artery ; not always per saltum, however, 

 because the smaller arteries do not pulsate, especially 

 if a tourniquet has been applied. 



And then the reason is the same wherefore the 

 pulmonary artery has not only the structure of an 

 artery, but wherefore it does not differ so widely in 

 the thickness of its tunics from the veins as the aorta : 

 the aorta sustains a more powerful shock from the left 

 ventricle than the pulmonary artery does from the 

 right ; and the tunics of this last vessel are thinner 

 and softer than those of the aorta in the same pro- 

 portion as the walls of the right ventricle of the heart 

 are weaker and thinner than those of the left ventricle ; 

 and in like manner, in the same degree in which the 

 lungs are softer and laxer in structure than the flesh 

 and other constituents of the body at large, do the 

 tunics of the branches of the pulmonary artery differ 

 from the tunics of the vessels derived from the aorta. 

 And the same proportion in these several particulars 

 is universally preserved. The more muscular and 

 powerful men are, the firmer their flesh, the stronger, 

 thicker, denser, and more fibrous their heart, in the 

 same proportion are the auricles and arteries in all 

 respects thicker, closer, and stronger. And again, and 

 on the other hand, in those animals the ventricles of 

 whose heart are smooth within, without villi or valves, 



