ON THE MOTIONS AND SOUNDS OF THE HEART. 245 
pression was exercised on the fingers during each movement of 
the ventricles towards the front of the chest. [By the term 
‘anterior surface’ of the ventricles, is meant the surface corre¬ 
sponding to the one called ‘ anterior ’ in the human heart.] 
When the ventricles were in their softened state their anterior 
surface was sometimes in contact with the sternum, and some¬ 
times a little removed from it ; and, from the contemplation of 
this and the preceding experiment, the Committee were satis¬ 
fied that the situation of the heart in the thorax is affected by 
the position of the body ; which observation has been made 
also by others. For instance, in the recumbent state on the 
back, the heart recedes somewhat from the sternum : if the in¬ 
dividual lie upon the face, the anterior surface of the ventricles 
is in constant apposition with the front of the chest, the pericar¬ 
dium, of course, being interposed. The yielding texture of the 
lungs, and the mode of attachment of the pericardium and 
great vessels, are such as to allow the gravitation of the heart 
to influence its position in different postures of the body. 
These experiments were repeated on different animals, and 
the observations recorded above were confirmed. 
Exp. 3. A rabbit was stunned, and its heart was immediately 
taken out of the body, and placed on the hand, with the anterior 
surface of the ventricles upwards. The ventricles continued to 
beat for some time, and assumed alternately the forms which 
have been described in the first experiment. During the con¬ 
tinuance of the globular form, the body of the ventricles was 
-protruded upwards, and their apex was elevated considerably 
from the hand; and while in this state it was ascertained, by 
measurement with a pair of compasses, that the length and the 
breadth of the ventricles were diminished. On the collapse, or 
softened state of the ventricles taking place, they became longer 
and flatter, and their apex sank towards the hand. The heart 
was now placed with the posterior surface of the ventricles up¬ 
wards, and a globular swelling in their middle part was observed 
to alternate with a flattened form, in this aspect also; but the 
apex was not elevated as in the preceding part of the experi¬ 
ment. 
Exp. 4, The sternum of a frog having been removed, the 
following appearances were observed. The ventricle, having 
become swollen, soft, and red-coloured, gradually sank and di¬ 
minished in size, and became pale, and hard to the touch ; alter¬ 
nating in these appearances with similar appearances in the 
auricle. It was manifest from the colour of both ventricle and 
auricle in their swollen state, that they were then full of blood, 
and from their softness, that they were in their diastole. When 
