Regarding cerebral symptoms, little can be said except that unconsciousness and coma may come on early and persist till death. In cases terminating fatally the animal seemed to be conscious, but so depressed that it was unable to stand or even move when called.
Concerning differences in the susceptibility of different animals to the poisons of Amanita muscaria, cats seemed to be more susceptible than dogs in the earlier experiments with extracts of the fresh fungus, but more numerous experiments with the dried fungus failed to show any greater difference than can be observed between different animals of the same kind.
As to the nature of the poisons very little can be stated from the experiments, as they were undertaken as a preliminary step to chemical studies to be carried on later. The alkaloid muscarine is one of our best known poisons and nothing can be added to what is already known about it. The poisons are extracted by distilled water as well as by a solution of sodium chloride; they are soluble in glycerine and in alcohol and very little difference can be seen in the action of these extracts, unless the alcoholic extract contains more of the muscarine, while the glycerine extract contains more of the other poisons.
It is stated that muscarine is not poisonous to flies; that the Amanita muscaria contains a volatile poison which is poisonous to flies (hence the name “Fly mushroom”), and which is lost by drying; that inhabitants of northern Asia use the dried fungus (after the volatile poison has been lost) for producing intoxication (Von Boeck in Ziemssen’s Cyclopedia, Vol. VII, p. 927). My experiments have been entirely with mammals and frogs, and unfortunately those performed with the fresh toadstools were not numerous enough to enable me to draw positive conclusions as to any loss of toxicity by drying. A single experiment with a cat seemed to indicate that boiling of the fungus lessened the toxicity but subsequent experiments indicated that a boiled solution was no less toxic than one not boiled.
One thing we can state definitely; that boiling the dried A. muscaria does not destroy its toxicity. This indicates that the poison is not of an albuminous nature, which would be coagulated by heat.
Whether or not any volatile poison is lost by boiling a solution of the fresh fungus or by drying at 40° C. can not be stated definitely as the experiments made with the fresh fungus were few in number on account of the extreme difficulty in getting them perfectly fresh.
The average of six observations in which it was possible to weigh the toadstools before and after drying at 40° C. showed a loss of 84.4 per cent. of water. In other words, 1 gram of the dried equals 6.4 grams of the fresh.
Comparing the lethal doses of the dried with the lethal doses of the fresh extracted by glycerine and alcohol, it does not appear that there is any great loss of the toxicity by drying as is shown by the following: Lethal dose of dried in Experiment 31 was .085 gram. per kilo of body weight; in Experiment 55, .033 gram. per kilo caused early death, while .223 gram. of dried per kilo and .120 gram. per kilo caused death from late effects (Exps. 32 and 57). The lethal doses of the fresh were .91 gram. per kilo (Exp. 29) and 1.055 gram. per kilo (Exp. 36) when a glycerine extract of the fresh growth was used, while 1.222 gram. per kilo (Exp. 16) made from an alcoholic extract failed to kill.
It may be well to introduce here the results of an experiment which shows there is no highly poisonous volatile material given off from the A. phalloides. This is rather an important fact to determine, as the opinion is held by some that there is a volatile poison, and most of my experiments were made with the dried fungus. A 1 per cent. solution of fresh A. phalloides was distilled until three-fourths of the fluid had passed over as distillate. The latter was injected into the vein of a dog and found not at all toxic. The opportunity has not been afforded me of repeating this experiment personally, but Dr. J.P. Arnold has kindly repeated it for me, injecting the distillate into rabbits and frogs and failed to find it toxic. Certainly if there is any volatile poison in the A. phalloides it must be either in very minute quantity or very slightly toxic.