Small amounts of the dried Amanita muscaria are said to be used by inhabitants of northern Asia for the stimulating effect upon the nervous system, producing, like other narcotic poisons, a dreamy state of intoxication, deepening into sleep (Von Boeck in Ziemssen’s Cyclopedia of Medicine, Vol. VII).
In animals the most striking effect is upon the circulation. When injected intravenously it causes tremendous inhibition of the heart’s action—a moderate amount causing the heart to beat slowly and powerfully; a large amount causing complete arrest. Even with the partial inhibition there is an enormous fall of pressure. The slowing of the heart soon passes off, and when a moderate amount has been injected, the circulation quickly returns to normal.
In one of my experiments on a dog, the heart stopped for 1¾ minutes and then began beating again, the circulation soon recovering.
Late in the poisoning the heart beats may be rapid and feeble and the blood pressure low. The lowered blood pressure is largely due to dilatation of the small blood vessels resulting from a loss of control over them by the nerve center which normally keeps the arterioles in a state of partial contraction.
The inhibition of the heart is due to the action of the well-known alkaloid muscarine upon nerve ganglia in the heart. The contraction of the pupil and the increased secretory activity of the glands are also due to this substance which was discovered by Schmideberg and Koppe in 1869.
It was soon found that although dogs recovered from the immediate or early effects (i. e., from the muscarine) of enormous quantities of toadstools, they succumbed from the late effects of much smaller quantities. Atropine fails to avert this result from the late effect, whether given before the poison, with it, or after it. The inhibition of the heart passes off long before death occurs. Late death does not appear to be due to muscarine.
All these facts put together point to the existence of some other poison or poisons in the Amanita muscaria to which atropine is not an antidote.
This peculiar poisoning causing death so late will be discussed again after considering the other poisonous mushrooms as they act similarly.
Gastro-intestinal symptoms were not as common in my experiments with Amanita muscaria as with the Amanita phalloides. Vomiting and purging occasionally occurred early, but much more frequently late in the poisoning and often not at all.
Convulsions did not occur in any of the animals poisoned by this fungus. Convulsions are recorded in some cases of poisoning in man, but not so constantly as with the A. phalloides and A. verna. Where they occurred either a large amount had been taken (as in Prentiss' case) or there is some doubt about the Amanita muscaria having been the only toadstool eaten (as in Caglieri’s cases). Frogs are very easily thrown into spasms, but no spasms were observed, even in fatal poisoning of them by this toadstool.