ON THE MOTIONS AND SOUNDS OF THE HEART. 191 
S. 6. In neither of the two preceding observations did the 
auricles and ventricles exactly alternate, but in each, whenever 
observation was carefully made, the auricular systole imme- 
diately preceded the ventricular; and the ventricular diastole 
preceded the pause or rest, which last was first interrupted by 
the abrupt auricular contraction. 
OsservaTions XIII. and XIV. 
July 15th.—Subjects, a Donkey {about a twelvemonth old, 
prepared with woorara ; very little blood lost in opening ; ani- 
mal not healthy, and weak, so as to be ill able to walk before the 
operation ; heart acted pretty well)—and a Dog. 
Phenomena: Donkey—Rhythm of motions ;—character of 
auricular actions ;—same, of the ventricular ;—double friction 
between heart and pericardium normally ;—eccentric impulse 
felt all over ventricles in systole ;—motions of cava. 
Phenomena: Dog—Normal double frictions of pericardium; 
—with other phenomena. 
S. 1. Rhythm of motions of the auricles and ventricles was 
as in former experiments ; first, the auricular systole, then im- 
mediately, the ventricular systole, without interval, and as if it 
were a continuation by undulation of the former motion. 
S. 2. Then the pause during which the auricle and ventricle 
became each distended and soft and flaccid, the former sliding 
its extreme margin downwards on the fundus of the ventricle 
toward the apex, to retract it suddenly again toward the 
sinus in systole,—and the latter protruding its apex and sides so 
as to be enlarged in every direction, except that of the trans- 
verse vertical diameter, to retract both apex and sides in the 
following systole, and at the same to rise upwards in its cen- 
tral parts with an impulse. 
S. 3. Before opening pericardium the condition of that sac 
was carefully observed, and it was noted, that while the peri- 
cardium remained stationary under all circumstances, the heart 
suffered much change in shape and size, so that there was in 
every part, and especially over the auricles, a to-and-fro motion 
of the cardiac pericardium on the external layer of that sac, a 
friction in one direction in systole and in the opposite in diastole. 
S. 4. The impulse before observed was obtained by the fin- 
ger applied to any part of the ventricle in systole. 
. 5. The cava observed, and a slight action was noted, viz. 
a diastole followed by a systole, the former with a wave-like 
sensation of motion from the heart downwards, and accompa- 
nying the auricular systole, and immediately preceding the ven- 
tricular. The separator above described was introduced into 
