INTRODUCTION 



As we are about to discuss the motion, action, and use of 

 the heart and arteries, it is imperative on us first to state what 

 has been thought of these things by others in their writings, 

 and what has been held by the vulgar and by tradition, in order 

 that what is true may be confirmed, and what is false set right 

 by dissection, multiplied experience, and accurate observation. 



Almost all anatomists, physicians, and philosophers up to the 

 present time have supposed, with Galen, that the object of the 

 pulse was the same as that of respiration, and only differed in 

 one particular, this being conceived to depend on the animal, 

 the respiration on the vital faculty ; the two, in all other respects, 

 whether with reference to purpose or to motion, comporting 

 themselves alike. Whence it is affirmed, as by Hieronymus 

 Fabricius of Aquapendente, in his book on "Respiration," which 

 has lately appeared, that as the pulsation of the heart and 

 arteries does not suffice for the ventilation and refrigeration of 

 the blood, therefore were the lungs fashioned to surround the 

 heart. From this it appears that whatever has hitherto been 

 said upon the systole and diastole, or on the motion of 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 it seems likely that other ends and offices will 

 thence arise, and that the pulsations and uses of the heart, like- 

 wise of the arteries, will differ in many respects from the heav- 

 ings 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 inter- 

 mediate between the diastole and the systole, contain air, and 



