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was very feeble. One of the frogs, weighing 31 g, expired after 5 hours; the 
other one, weighing 40,5 g, survived. 
Experiment No. 4. Two frogs, 39 and 41 g respectively, each received 
0,1 g piperonal in emulsion. The symptoms were the same as before. Both 
frogs recovered. 
Experiment No. 5. Two frogs weighing 41 and 47 g, each received 
0,12 g piperonal. Both animals became very ill, and only commenced to re- 
cover after 12 hours. 
Piperonal therefore paralyses in frogs the central nervous 
system. In subcutaneous injections the action is extremely 
rapid. The fatal dose amounts to about 2,5 g per kilogram 
weight of the frog. 
As piperonal in frogs has especially the effect of paralysing the 
centra of the nervous system, the morbid symptoms produced by 
piperonal should be allayed, or possibly their complete disappearance 
be effected, by means of agents which stimulate the same nerves. 
Experiment No. 6. A small frog received 0,17 g piperonal, which for 
this animal was almost double the fatal dose. As the piperonal emulsified in 
acacia, in spite of the finest possible trituration, frequently clogged the small 
tubes of the syringes, an oil-emulsion was employed in the two following 
experiments. The oil was heated to 38 to 40°, then violently agitated, and 
rapidly cooled to the temperature of the room. The piperonal suspended in 
the oil remained, even at this low temperature, for a few minutes in a 
molten state. 
In the body of the frog the piperonal commenced to act only after 
20 minutes, and not until after hours had the reflex- action almost com- 
pletely disappeared. 
Occasionally very slight twitchings could be observed, which occurred 
simultaneously at all the extremities. After an hour 0,00005 g strychnine 
nitrate was injected. An hour after the strychnine-injection the first slight 
twitchings showed themselves on stimulation, and reached their maximum 
intensity after 2 hours. Convulsions or tetanus did not occur. A control-frog 
received only 0,00005 g strychnine nitrate. After 1^2 hours it was suffering 
from the most severe tetanus. After 20 hours the frog was only slightly in- 
disposed, but it was still so exhausted that it tolerated the dorsal position. 
It had only recovered completely after 30 hours. 
Experiment No. 7. A small frog received 0,00005 g strychnine nitrate. 
After hours, when suffering most severely from tetanus, 0,16 g piperonal 
in oil was injected. An hour after the injection only slight convulsions, but 
no tetanus, occurred. These convulsions also changed in the course of an 
hour into slight twitches. Like the other frog which had received first an 
injection of piperonal and subsequently one of strychnine, this one, after 
20 hours, was also only somewhat exhausted, and after 30 hours had com- 
pletely recovered. 
Strychine, therefore, is for frogs a remedy which com- 
pletely counteracts the paralysing action of piperonal, even 
when the latter is administered in double the fatal dose. 
Per contra, piperonal is an excellent antidote against strych- 
nine poisoning. 
