io On the Heart and Blood 



the heart and arteries, has been said with especial 

 reference to the lungs. 



But as the structure and movements of the heart 

 differ from those of the lungs, and the motions of the 

 .arteries from those of the chest, so seems it likely that 

 other ends and offices will thence arise, and that the 

 pulsations and uses of the heart, likewise of the arteries, 

 will differ in many respects from the heavings and uses 

 of the chest and lungs. For did the arterial pulse and 

 the respiration serve the same ends ; did the arteries in 

 their diastole take air into their cavities, as commonly 

 stated, and in their systole emit fuliginous vapours by 

 the same pores of the flesh and skin ; and further, did 

 they, in the time intermediate between the diastole and 

 the systole, contain air, and at all times either air, or 

 spirits, or fuliginous vapours, what should then be said 

 to Galen, who wrote a book on purpose to show that by 

 .nature the arteries contained blood, and nothing but 

 blood ; neither spirits nor air, consequently, as may be 

 readily gathered from the experiments and reasonings 

 contained in the same book ? Now if the arteries are 

 filled in the diastole with air then taken into them (a 

 larger quantity of air penetrating when the pulse is large 

 and full), it must come to pass, that if you plunge into 

 a bath of water or of oil when the pulse is strong and 

 full, it ought forthwith to become either smaller or 

 much slower, since the circumambient bath will render 

 it either difficult or impossible for the air to penetrate. 

 In like manner, as all the arteries, those that are deep- 

 seated as well as those that are superficial, are dilated 

 at the same instant, and with the same rapidity, how 

 were it possible that air should penetrate to the deeper 

 parts as freely and quickly through the skin, flesh, and 

 other structures, as through the mere cuticle ? And 

 how should the arteries of the foetus draw air into their 

 cavities through the abdomen of the mother and the 

 body of the womb ? And how should seals, whales, 

 dolphins, and other cetaceans, and fishes of every 



