. ON THE MOTIONS AND SOUNDS OF THE HEART. 193 
not separated by any very distinct interval from the instantly 
succeeding ventricular sound, which however it preceded ra- 
ther, and certainly preceded to the senses of touch and hearing 
together, the hardening and rounding of the ventricle. 
8. 7. In the dog, as in the ass, the motions were slow com- 
paratively in the heart, auricles as well as ventricles. The right 
ventricle first, and afterwards the left ventricle, were punctured 
with a slender glass tube drawn out for a couple of inches at 
the lower end, and the result observed. In systole there was 
a sudden rise in the tube, and a slight subsidence in diastole. 
The subsidence was but slight, the greatest not being in the 
left ventricle more than half an inch, and in the right ventricle 
still less. The sinking of the blood in the tube in diastole was 
such as might be caused by a sudden withdrawal of an impulse 
sufficiently energetic (like that of the systole) to overcome gra- 
vitation abruptly, and so as to excite a jet in a tube containing 
a fluid column sustained by a constant pressure (such perhaps 
as might be produced by the venous influx) from below. 
S. 8. In both hearts the right cavities were relieved from 
distension before complete cessation of action, and the areas of 
the ventricles, judging by apparent extent of walls opened and 
spread out, seemed in no degree to differ. 
OxssERVATIONS XY. and XVI. 
July 18th.—Operated on two Donkeys of from four to eight 
months old. 
Phenomena : First donkey— Glass tubes introduced into left 
auricle and ventricle, and results noted ;—normal pericardial 
Srictions observed, and several other observations confirmed : 
Second donkey—Blunt hook and screw, successively interposed 
between mitral valves with considerable modification of first 
sound ;—also, spontaneous abnormal sounds ;—auricular SY- 
stolic sound ;—results of introduction of glass tubes into heart's 
cavities ;—confirmation of former observations. 
Woorara injected in each case; in the first, the operation 
very successful, but in the second, a second dose of two grains 
required. 
In the former, much blood lost, viz., probably owing to an 
accidental cut made in hastily opening the trachea for artificial 
breathing. The heart found acting rapidly, hurriedly, and with 
a rhythm unfavourable for observation. Second sound not di- 
stinct. The experiments intended were two, viz., stopping the 
mitral valves by an interposed blunt hook introduced through 
auricle, or by a screw-shaped wire similarly admitted; but owing 
probably to profuse hemorrhage, the first sound was not suf- 
VOL. Ix. 1840. o 
