OF THE BARK OF ERYTHROPHLEUM GUINENSE. 
643 
The thorax was then opened, and the heart found beating ; respiratory movements 
recommenced on opening the thorax. 
The bladder was found greatly distended ; there had been micturition during the 
experiment, which was probably only overflow. 
Remarks. 
We append a diagram (p. 652) showing the coincident variations of blood-pressure 
and secretion of urine, which will be more fully commented on later. (Vide effect on 
urinary secretion.) 
So far as the phenomena of correlation are concerned, this experiment shows that 
while a small dose of casca slows the pulse, an additional one greatly quickens it. This 
action of casca closely resembles the effect of digitalis, which first slows the pulse by 
stimulating the vagus-roots, and then quickens it by paralyzing the ends of the vagus 
in the heart. It therefore seemed probable that the cardiac ends of the vagus would 
be found to be paralyzed by large doses of casca. 
It was possible that the primary slowing of the heart’s action might be due to stimu- 
lation of the inhibitory apparatus in the heart itself, and not to the action of the drug 
on the vagus-roots. Two questions, therefore, were to be settled:— 
1st. Is the primary slowing of the pulse due to stimulation of the vagus-roots, or to 
stimulation of the inhibitory apparatus in the heart 1 
2nd. Is the secondary acceleration of the pulse due to paralysis of the ends of the 
vagus in the heart ? 
To answer these questions the following experiment was performed. 
Experiment XXXIV. — March 21. 
Action on the Heart and Arterial Pressure of a small dose of Casca. 
A dog weighing 8 lb. was chloroformed, and kept under chloroform during the 
experiment. 
A cannula was inserted into the right carotid and into the right femoral vein. 
Time. 
Blood- 
pressure. 
Pulse in 
10 seconds. 
Oscilla- 
tions. 
Respi- 
ration. 
in. s. 
millims. 
millims. 
Condition before injection 
110 
18* 
10 
0 551 
1 0 
7 cnb. centims. -gfo watery solution injected into fe- 
J 125 
16$ 
10 
X U I 
1 10 1 
► 
moral vein „ 
\ 130 
16 
10 
1 20 J 
Rise of blood-pressure. Commenced prolongation of 
diastole 
155 
14 
10 
1 45 
Systole fairly sharp, diastole very long 
140 
5 
40 
Commencing fall of blood-pressure. 
2 51 
Great fallof blood-pressure and lengthening of diastole. 
65 
3 
25 
2 20 1 
r 
Diastole extends over 15 seconds. 
Systole extends over i second ; does not vary with 
respiration. 
1 
4 Y 
MDCCCLXXVII. 
