Effects of poisons on the pulsations.—Dogiel has also experimented on the influence of poisons in the form of vapor or as liquid solutions on the pulsations of insects, which is much as in vertebrates. The application of carbonic oxide to the larva of Corethra, whose heart one minute previous to the poisoning beat 15 times a minute, accelerated the heart-beats in about 55 minutes to 25 pulsations in a minute. Afterwards there was a retardation in the pulse to the normal beat. Carbonic acid had a similar effect.
The following results obtained by Dogiel are somewhat as tabulated by Kolbe:—
I. Substances which cause the pulsations of the heart to accelerate.
a. An induction current of electricity, acting feebly.
b. Ammonia, acting feebly.
c. Ethyl ether, acting feebly.
d. Oxalic acid, acting feebly.
e. Carbolic acid, acting feebly.
f. Potassium nitrate, acting feebly.
g. Aconite, acting feebly.