10 ON THE HEART AND BLOOD. 



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 inter- 

 mediate 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 pene- 

 trate 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 description, living in the depths 

 of the sea, take in and emit air by the diastole and systole of 

 their arteries through the infinite mass of waters ? For to say 

 that they absorb the air that is infixed in the water, and emit their 

 fumes into this medium, were to utter something very like a mere 

 figment. And if the arteries in their systole expel fuliginous 

 vapours from their cavities through the pores of the flesh and 

 skin, why not the spirits, which are said to be contained in these 

 vessels, at the same time, since spirits are much more subtile 

 than fuliginous vapours or smoke ? And further, if the arteries 

 take in and cast out air in the systole and diastole, like the 

 lungs in the process of respiration, wherefore do they not do the 

 same thing when a wound is made in one of them, as is done 

 in the operation of arteriotomy ? When the windpipe is di- 

 vided, it is sufficiently obvious that the air enters and returns 

 through the wound by two opposite movements ; but when an 



