FIFTH REPORT — 1835 . 
246 
they became pale and diminished in size they were in their sy¬ 
stole. During the diastole of the ventricle its anterior surface 
was prominent, and approached the sternum, while its apex 
drooped towards the spine. In its systole, the anterior surface 
receded from the sternum, and its apex was slightly turned 
upwards. The finger being applied to the ventricle during its 
systole, a slight shock or impulse was felt. 
In this experiment, the relations between the sternum and 
ventricle, during the diastole and systole of the latter, are nearly 
the reverse of those observed in the heart of quadrupeds in the 
preceding experiments. In them the ventricles approach the 
sternum during the hardened state, or systole, and recede from 
it in the softened state, or diastole. This difference depends 
upon the dissimilarity of the heart in the warm-blooded and in 
the cold-blooded animals, and will be adverted to again. 
§ 2. Experiments on the Sounds of the Heart. 
Exp. 5. A stethoscope was applied on the sternum over the 
heart, in a calf in which artificial respiration had been esta¬ 
blished, and both sounds of the heart were distinctly heard : 
the first prolonged and dull, the second abrupt and clear. The 
sternum and ribs were removed, so that the heart moved free 
from contact with any part of the thorax; and a flexible ear- 
tube having been placed on the pericardium, over the ven¬ 
tricles, both sounds were distinctly heard. [In the experiments 
on the sounds of the heart, with the sternum removed, the 
flexible ear-tube was found to be of much service, in preventing 
the transmission of the shock or impulse which was felt when 
the common stethoscope was used, and which embarrassed the 
observations.] The ear was now applied near to but not touching 
the heart, and both sounds were distinguishable, but feeble. A 
small piece of board was placed over the surface of the ventricles, 
and kept in contact with the pericardium, and by a stethoscope 
applied upon the board, both sounds were heard as distinctly, 
and very nearly as strongly, as when heard through the sternum. 
The ear-tube was placed on the ventricles, near their apex, and 
in this position the first sound was very distinctly heard ; the 
second sound indistinctly. When the ear-tube was placed over 
the origins of the large arteries, both sounds were heard distinctly, 
the second particularly so. The pericardium was distended 
with tepid water, and in that state both sounds were heard by 
the ear-tube applied to its surface, but not so clearly as before 
the injection of water. 
Exp. 6. In a calf, the sternum and ribs having been removed 
