198 REPORT— 1840. 
Phenomena: Donkey—Negative character of diastole. 
Dog—Apex cordis threaded and held tense in the direction 
of the mesial plane of the subject. Results: change of shape 
and size of the heart in systole and diastole, and visible mo- 
tions ;—glass tube passes into cava inferior ; results ;—columne 
carnee and parietes electrified ; results ;—cavities compared 
post mortem and found equal. 
8.1. Glass tubes introduced into the left ventricle at fundus, 
and apex, and in each a column rose and at length overflowed, 
having a slight subsidence at each diastole, and sudden eleva- 
tion at each systole ; but no well-marked difference between the 
times of rise and fall in the tubes was detected. 
8. 2. The heart acted for some time with considerable energy, 
notwithstanding great hemorrhage, but soon failed after being 
perforated. The heart was then cut out while yet contracting 
vermicularly, and electricity was applied so as to permeate the 
columnz and parietes, but no satisfactory action was obtained. 
The cavities of the heart had been for some time much dis- 
tended, from loss of irritability before excision. 
OBSERVATION XX. 
A Terrier-dog, stout though small, was then stunned by a 
blow on the head ; the chest was rapidly opened, and artificial 
breathing established. 
S.1. The apex cordis was then threaded, and at each sy- 
stole a pull at the chord was observed, followed by relaxation, 
and the tension and relaxation of the string alternated ; the 
former coinciding with systole, and the latter with diastole. 
(Note.—The string was drawn in the line of the longitudinal 
axis of the heart.) Dr. Boyd at one time kept the string firmly 
extended and permanently tense, by holding his hand as far 
away as the string would allow, for a short space, and then 
maintaining his position, but relaxing his hold so as to allow 
the string liberty to slide between his fingers when drawn away; 
and the result was, that before the experiment was suspended, 
an inch or more of the string appeared to have passed between 
his fingers, one eighth of an inch at least being pulled through 
at each systole. 
S. 2. After this observation had been made and repeated to 
the satisfaction of all parties, the heart acted still with much 
vigour, and both sounds were distinctly audible, notwithstand- 
ing great loss of blood. Also the diminution of the horizontal 
transverse and of the longitudinal diameter, and the increase 
of the vertical transverse diameter, with sudden bulging up- 
wards of the fundus and central parts, were very plain to the 
