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DR. T. L. BRUNTON AND MR. W. PTE ON THE ACTION 
minutes the heart in casca stopped entirely, that in salt solution pulsated feebly at the 
rate of 3 per 10 seconds. In 15 seconds more it stopped. 
In Experiment XXVIII. we repeated the foregoing experiment with a much stronger 
casca solution. The hearts at the commencement of the experiment were beating at 
the rate of 4 per 10 seconds. At the end of 30 minutes the heart, B, in casca, which 
had previously got very slow and weak, stopped, while the standard heart, A, was still 
beating strongly and regularly at the rate of 4 per 10 seconds. 
Experiment XXIX. — March 7. 
The heart of a frog whose cerebrum had been destroyed was exposed. Pulse 72 
before injection, 
h m 
11 40. Injected 2 cub. centims. alcoholic solution beneath skin of back. 
11 50. Pulse 60 ; regular. 
12 2. Pulse 48. 
12 10. Pulse 60. Clonic convulsions. 
12 15. Ventricle stopped in systole, firmly contracted in its greater part, with a pouch- 
like dilatation of a small portion. Auricles still contracting. 
12 27. Ventricle firmly contracted. Still partial contraction of auricles. Respiration 
and slight convulsive movements continue. 
12 50. Removed from frog-board. The ventricle is not so firmly contracted. Still 
respiring and occasionally convulsed. 
1 0 p.m. Ventricle relaxed. Slight movements of it have recommenced. 1*4 cubic 
centim. alcoholic solution again injected. 
1 7. Ventricle again firmly contracted. No respiration. Still slight reflex movement. 
1 30. Died with heart in same condition. 
Experiment XXX.— May 10. 
The heart of a frog was exposed, and a little extract of casca placed on it. Pulse 34 
per minute. 
It had no apparent action. 
A watery solution of casca was then poured into the thorax. The pulse became 
slower, =24 per minute. 
The ventricle then expanded irregularly ; the diastole at the base being later than 
that at the apex. 
Then the distention became imperfect, the ventricle seeming wrinkled. 
The heart then stopped in systole, having two pin-point dilated pouches on it. 
These experiments show that a very weak solution of casca applied to a frog’s heart, 
when removed from the body, slows its pulsations, Avhile, after the application of a 
stronger solution, the pulsations become slow, then the systolic contraction ceases to take 
place instantaneously over the whole surface of the ventricle ; lastly the heart stands still 
in systole. 
