ON THE MOTIONS AND SOUNDS OF THE HEART. 189 
contracted on the point of a scalpel being applied to the left 
ventricle. 
OsBsERVATIONS XI. and XII. 
July 11.—Phenomena: Stroke and sound obtained as if from 
locomotive force in systole of ventricles ;—rhythm of the heart's 
motions ;—manner of auricular action ;—same of the ventri- 
cular-venous motions ;—mechanism of the cardiac throb or im- 
pulse ;—mode of hemorrhage from a wounded auricle. 
Subjects, two Donkeys operated on; one about six weeks 
old, the other about two and a half months; both rather weak 
from fasting twenty-four hours, owing to being too young to 
eat or drink properly. Each heart ceased to beat after about 
half an hour. First animal had his forehead beaten in so as to 
stun him, and chest then opened. Heart acted quickly and not 
very regularly. No distinct second sound ; no auricular sound. 
S.1. Before opening pericardium, a hard flat body, having 
a piece of lead weighing about a quarter of a pound fixed on 
it, was placed on the heart, and a stethoscope was held at a 
short distance over it, z.e. ata quarter to half an inch, and at 
each systole of the heart the lead rose up abruptly and struck 
the stethoscope with a tick, audible at some yards distance, 
and receded with diastole to sometimes nearly half an inch, 
and again rose up and impinged on the tube in systole, and 
so on. 
S. 2. The pericardium was then opened, and the auricles 
and ventricles observed. No auricular sound could be detected. 
The auricles acted immediately before the ventricles, and after 
the pause or rest, and very abruptly and rapidly: the heart acted 
rapidly, probably considerably above one hundred per minute. 
S. 3. The auricles were observed in systole to dimple and 
contract all round from periphery to centre, as in former ob- 
servations. 
S.4. The changes of shape in the ventricles were particu- 
larly plain and striking—the apex moved slightly upwards and 
to the left, and was drawn toward the base in systole, while 
the horizontal transverse diameter of the heart, as the animal 
lay on its right side, was diminished, and the transverse verti- 
cal diameter, and that alone, was increased, owing to the heart 
becoming from flattish, inferiorly and superiorly, convex, and 
from in the centre compressed or depressed, strictly globular 
or protruding, so that the central longitudinal axis was elevated 
during systole, and lowered in diastole, while in diastole 
the apex rather approached the sternum from which it had 
receded in systole, owing to shortening of the organ. 
S. 5. The veins were observed, and except perhaps a slight 
