This section is from the book "A Guide To The Poisonous Plants And Weed Seeds Of Canada And The Northern United States", by Robert Boyd Thomson, H. B. Sifton. Also available from Amazon: A guide to the poisonous plants and weed seeds of Canada and the northern United States.
The genus Amanita contains the most commonly known, as well as some of the most deadly of our poisonous mushrooms or "toadstools" as they are colloquially called. The top of the cap may have various colours, but the gills are always white, or only very slightly tinged. The stem is bulbous at its base. While a few species of Amanita may be eaten with impunity, a large proportion are known to be deadly poisonous, and two in particular give trouble in Canada. It must be distinctly understood, however, that while we have limited our description to these two species of Amanita, there are many other poisonous forms, and no one should use as food any mushroom with which he is not familiar.
Other Common Names: Fly Amanita, Fly Fungus, Fly Killer.
This mushroom is not confined to the Western Hemisphere. It is native also to Europe and Asia where its name originated from the fact that it has for centuries been used as a poison for flies. Its natural place of growth is not in pastures but in woods. Nevertheless, records show that cattle are sometimes poisoned by it. In northeastern Asia the fungus is used in the manufacture of an intoxicating drink, notwithstanding the fact that many deaths result from over-indulgence.
The alkaloid muscarin is the chief poison which has been isolated. It acts on the nerve centres, producing the nervous symptoms. Bruce and Lond mention it as the only known substance which specifically contracts the pulmonary vessels. It is stated that .003 to 1005 gram of muscarin is a very dangerous dose for a man. The amount present in the fungus varies greatly under different conditions. Moreover, a varying amount of the alkaloid pilz-atropin also contained in the mushroom neutralizes the muscarin to a greater or less extent. It is probably owing to the
The Poisonous Constituent presence of this chemical in considerable quantities that in parts of France and Russia Amanita muscaria is used as food without harmful results. As ordinarily found in this country, however, the fungus has proved again and again to be deadly poisonous.
Fig. 27. - Death Cup - Amanita phalloides.
Fig. 28. - Fly Agaric - Amanita muscaria.
The poison is moderately rapid in its action, the symptoms usually, though not always, beginning within two hours after eating. The heart's action becomes slow and breathing is difficult. The nerves are so affected as to produce giddiness, cold sweat, and a deep stupor, which may last for hours or days. There may be no abdominal pain, and after the stupor has commenced the most powerful emetic often fails to produce vomiting. The patient may linger for two or three days before death ensues as a result of stoppage of the heart's action.
The following treatment is recommended by Chesnut: "The treatment for the Fly Amanita poison consists primarily in removing the undigested fungus from the alimentary canal, and in counteracting the effects of the muscarin upon the heart. The action of this organ should be fortified at once by hypodermic injections, by a physician, of some heart stimulant, preferably atropin, in doses of from 1-100 to 1-50 of a grain. As a stimulant emetic, mustard is particularly valuable. If this is not effective, apomorphin should be administered hypodermically by a physician; tannin is of little or no value in rendering the muscarin insoluble in the stomach. If vomiting has not taken place, recently burned charcoal may be administered for its mechanical effect in absorbing the poison, or a couple of grains of permanganate of potash in a 1 per cent alkaline solution to decompose it. The use of this substance should be followed by oils or oleaginous purgatives, and the lower intestines should be washed out with an enema of warm water and turpentine. The use of atropin must be governed by the symptoms, but it is advisable to push it heroically, for in this alkaloid we have an almost complete physiological antidote to the poisonous principles of the Fly Amanita. Experiments on animals poisoned by this fungus and also by muscarin extracted from it have very clearly demonstrated that when the heart has nearly ceased to beat it may be stimulated almost instantly by a hypodermic injection of atropin. Its use, as thus demonstrated, has been the means of saving numerous lives. Muscarin may be dissolved out of the Fly Amanita to a great extent by vinegar, but the possible existence in the plant of such compounds as phallin (described under Death Cup, p. 114), makes its use extremely dangerous."
The Fly Agaric grows on the shady borders of fields and especially in coniferous forests, and is one of the largest of our mushrooms. The cap is yellow to orange red, shining and warty, with a slightly striate margin. The gills are white. The stem, four to six inches long and about half an inch thick, terminates below in a scaly bulb.