ON THE MOTIONS AND SOUNDS OF THE HEART. 
247 
as in the last experiment, and the pericardium having been cut 
away, both sounds were heard, by the ear-tube applied to dif¬ 
ferent parts of the ventricles, in the same manner as in the last 
experiment. The great arteries were compressed close to the 
heart; and the character of the second sound was altered; and 
at times it seemed to some of the Committee that the second 
sound was lost, the first sound remaining. A fine curved 
needle was passed into the aorta, and another into the pulmo¬ 
nary artery, beneath the line of attachment of one of the semi¬ 
lunar valves in each vessel; and the needles were passed up¬ 
wards, about half an inch, and out again through the respective 
vessels, so as to confine a valve in each, between the needle and 
the side of the artery. Upon applying the ear-tube over the 
origins of the arteries, it was found that the second sound had 
ceased, and that a sound resembling the first, and coinciding 
with the systole of the ventricles, was still audible. Some of 
the members of the Committee thought that the sound just men¬ 
tioned was prolonged beyond the usual duration of the ‘first,’ 
or ‘ dull’ sound, which had been heard before the introduction 
of the needles ; and, towards the termination of the experiment, 
it was observed by some of those present, that there seemed to 
be a repetition of the sound called ‘first’, or to be two pro¬ 
longed sounds, similar to each other, and v 7 hich might be cha¬ 
racterized as ‘ rushing’ sounds. When the heart w T as removed 
from the body, and the semilunar valves examined, it was found 
that one valve in each artery had been confined against the side 
.of the vessel, so as completely to prevent its descent. [It may 
be remarked that this operation can be very easily performed, 
and almost with certainty of success.] 
Exp. 7. The foregoing experiment was repeated on another 
calf, and with the same result,—the cessation of the second 
sound. During the experiment the second sound, somewhat 
modified, was heard to recur; and, upon examination, it was 
found that the needle which had been passed into the aorta 
had slipped out. On its being replaced, the second sound 
again ceased. On taking out this heart also, the valves were 
found to have been confined, as in the last experiment. 
Exp. 8. A calf having been stunned, the heart was taken out 
quickly, and placed on the table. The ear-tube was applied to 
the surface of the ventricles while still beating, and at each 
systole a sound was heard resembling that called the ‘first’ 
sound: no second sound was audible. When the heart had 
ceased to beat, the ventricles were filled with water, and the 
heart being held upright, the ear-tube applied to the ventricles ; 
and these suddenly compressed with the hand, a sound resem- 
