486 Prof. J. T. Cash and Dr. W. R. Dunstan. [May 24, 
Perfusion of the Heart with Pseudaconine (from Pseudaconitine), Fig. E.— 
Strengthening of the ventricular systole ensues when a few cubic centimetres 
of solution (containing 0°02 of alkaloidal salt per 20 c.c. of menstruum) are 
perfused (Ez), and this effect is still apparent when 20 to 30 cc. (Es) have 
been passed slowly through the organ. When 60 to 70 c.c. have passed, 
a delay in the systolic phase with retarded relaxation occurs, (E,), and 
beyond this amount the systole becomes distinctly feebler (E;). A spon- 
taneously contracting preparation beats more slowly after small and 
moderate doses of pseudaconine. MRinger’s solution perfused through the 
organ, which shows evidence of the action of large doses of pseudaconine, 
is usually sufficient to restore the original strength of contraction. 
Action on Muscle and Nerve-—When such a proportion of pseudaconine 
(from pseudaconitine) as 1 gramme per kilogramme is injected into the 
dorsal sac of a brainless frog in which one sciatic is exposed, it is found that 
on stimulating the peripheral end of the nerve, the contractions soon become 
feebler and remain altogether absent, if the stimulation is frequently 
repeated with but brief rest intervals. After a pause contractions are again 
elicited, and this phenomenon may be reproduced until under a further and 
increasing action of the alkaloid, all response to faradisation is eventually 
lost. According to the dose employed, this absence of response may last 
for some hours or even for a day or two. The same rapid exhaustion of 
excitability under stimulation, is witnessed during the earlier phases of 
recovery of excitability of the intramuscular motor nerves. In the 
uninjured animal recovering from pseudaconine, the inability to perform 
a series of spontaneous movements, as well as the rapid failure of the 
reflexes when a sufficient rest interval is not assured, is due to the same 
condition. The separated nerve muscle preparation gives the reaction which 
might be anticipated. 
Expervment.—In a pegged frog (#. temporaria) a vascular ligature was 
applied to the left leg, and pseudaconine (from pseudaconitine) was injected 
under the skin of the abdomen in the proportion of 0°3 gramme per kilo- 
gramme. In 45’, when all reflex had disappeared from the open side, two 
muscle nerve preparations were made, one from either leg, and tested by 
faradisation. The minimal excitability on the ligatured side was 15 cm. for 
indirect and 9 for direct stimulation; on the open side 10 and 8 respectively. 
The tracings are the result of a series of 3’ faradisations delivered every 
10’’ in the first series (F,),every 20’ in the second series (F’1), and every 15’ 
in the third series (F’;). The muscle directly stimulated yields strong and 
well sustained contractions. This is, therefore, the result of a slight action of 
pseudaconine, less than one-fifth of the lethal dose having been administered. 
