192 REPORT—1840. 
the mitral aperture and a murmur was heard; but the heart 
ceased too soon, owing to errors in the insufflation, to allow of 
the experiment being properly followed out. 
OBSERVATION XIV. 
Same day. A Dog,small, and perhaps two years old, was poi- 
soned with prussic acid, and then prepared as usual. The 
heart acted pretty well for nearly half an hour. 
S. 1. The stillness or inertness of the free pericardium and 
constant succession of changes of shape and size in the heart 
were carefully observed ; the heart being, for the size of the 
animal, much larger than that of a donkey; the experiment was 
much less troublesome from that cause as well as from the 
greater facility of manipulation of a smaller animal. Every sy-- 
stole of the auricles produced a double friction, viz., one against 
the external layer of the pericardium and one against the fun- 
dus of the ventricles, or periphery of the auricular orifices ; 
and every diastole of course produced friction in the opposite 
directions ; and every systole of ventricle produced friction 
longitudinally from apex to fundus, and transversely from side 
to side, all round the body of the heart; while every ventricu- 
lar diastole included friction in the opposite directions. 
S. 2. The rhythm of the heart’s motions was as before, viz., 
first, the auricular systole,—and secondly, immediately there- 
after, the ventricular, and without marked interval, but, as if the 
latter motion were but a continuation of the former, by a sort 
of continued undulation,—and thirdly, the pause consisting first 
of auricular diastole, and then including the immediately suc- 
ceeding ventricular diastole, and interrupted first by the au- 
ricular systole. 
S. 3. Cava observed and motion noted, viz., a diastole fol- 
lowed by a systole, the former synchronous with the auricular 
systole, the latter immediately following. 
S. 4. The subclavian artery laid bare unintentionally for 
several inches, forming an arch more than two inches in length, 
and observed to lengthen without straightening in the systole 
of the heart, and to shorten slightly but sensibly in ventricular 
diastole. 
S. 5. As in every former distinct observation, the sensation 
of impulse was perceptible on every portion of the ventricular 
surface ; the shortening, rounding, hardening, and elevation of 
the central longitudinal axis, and increase of the transverse 
vertical diameter alone, of the body of the heart, easily distin- 
guished,—also the jerking over the orifices, &c., &c. 
8. 6. The auricular systoleapparently audible, but the sound 
