AN ANATOMICAL DISQUISITION 



MOTION OF THE HEART AND BLOOD IN ANIMALS. 



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 re- 

 spects, whether with reference to purpose or to motion, com- 

 porting themselves alike. Whence it is affirmed, as by 

 Hieronymus Fabricius of Aquapendente, in his book on ' Re- 

 spiration/ 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, 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 seerns 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 



