HEART AND BLOOD. ?i 



CHAPTER II. 



OF THE MOTIONS OF THE HEART, AS SEEN IN THE DISSECTION 

 OF LIVING ANIMALS. 



IN the first place, then, when the chest of a living animal is 

 laid open and the capsule that immediately surrounds the 

 heart is slit up or removed, the organ is seen now to move, 

 now to be at rest; there is a time when it moves, and a time 

 when it is motionless. 



These things are more obvious in the colder animals, such 

 as toads, frogs, serpents, small fishes, crabs, shrimps, snails and 

 shell-fish. They also become more distinct in warm-blooded 

 animals, such as the dog and hog, if they be attentively noted 

 when the heart begins to flag, to move more slowly, and, as it 

 were, to die: the movements then become slower and rarer, 

 the pauses longer, by which it is made much more easy to per- 

 ceive and unravel what the motions really are, and how they are 

 performed. In the pause, as in death, the heart is soft, flaccid, 

 exhausted, lying, as it were, at rest. 



In the motion, and interval in which this is accomplished, 

 three principal circumstances are to be noted: 



1. That the heart is erected, and rises upwards to a point, 

 so that at this time it strikes against the breast and the pulse is 

 felt externally. 



2. That it is everywhere contracted, but more especially to- 

 wards the sides, so that it looks narrower, relatively longer, 

 more drawn together. The heart of an eel taken out of the body 

 of the animal and placed upon the table or the hand, shows 

 these particulars; but the same things are manifest in the 

 heart of small fishes and of those colder animals where the 

 organ is more conical or elongated. 



3. The heart being grasped in the hand, is felt to become 

 harder during its action. Now this hardness proceeds from 

 tension, precisely as when the forearm is grasped, its tendons 

 are perceived to become tense and resilient when the fingers 

 are moved. 



4. It may further be observed in fishes, and the colder 

 blooded animals, such as frogs, serpents, &c., that the heart, 



