Journal of Proceedings. lv
of mushroom-poisoning, and a doctor is not within reach, you cannot do
wrong if you at once administer an emetic, and follow it up by a dose of
castor oil.
What the essential poison of all poisonous Fungi is has not yet been
satisfactorily made out. The only active principles which have hitherto
been isolated have been derived from Agaricus (Amanita) muscarius.
They are both alkaloids, of no very complicated constitution chemically.
The most important is muscarine, which was discovered only ten years
ago; twenty or thirty pounds weight of the fungus is required for the
extraction of a single drachm, and a grain of the alkaloid is worth
about a shilling. Many physiological observations have lately been
made upon this substance, and great interest attaches to it from its
almost complete antagonism to the action of atropia (the alkaloid
extracted from Belladonna). Atropia applied to the heart of a frog
will stop it, but a mere trace of muscarine applied to the so paralyzed
organ will sometimes restore the pulsations even after the heart has
ceased beating for four hours. But it is important to remember,
when we think of using atropia as an antidote to muscarine, that the
physiological antagonism is not quite complete, and that some of its
side actions might intensify some of the poisonous influences of
muscarin.
The other known derivative is amanitine. Its chemical name, "tri-
methyl-ox-ethyl-ammonium hydrate," is rather formidable, but its
action is much less intense than that of muscarine. It is interesting
mainly from the fact that precisely the same alkaloid can be obtained
from bile, when it is termed choline ; from brain and other nerve tissue,
when it is called nervine, as well as from eggs, the milt of salmon, &c.;
so strangely are Fungi and the animal kingdom linked together.
Amanitine can be formed artificially, by synthesis ; and by the action of
strong nitric acid it can be converted into muscarine by the loss of merely
two atoms of hydrogen.
The curious change of colour noticeable in Boletus luridus, from white
to blue, on exposure to the air, would seem to point to some active
principle; but my friend Mr. Charles G. Stewart, of St. Thomas's
Hospital, tells me he cannot hope to find out much about it unless
he has about half a hundredweight of the Fungus to experiment upon ;
he has extracted an amorphous changeable substance, which is neither
indigo nor any aniline derivative, but he has not succeeded in
isolating it.
Other principles are said to have been extracted from Fungi, but
nothing else of importance is known about what makes any of them
poisonous.
You will be disappointed if I do not enumerate those British Fungi
which are known to be poisonous ; you will be surprised to hear how few
are those which have been proved to be so. Perhaps the reason of this
is the caution natural to scientific fungus-eaters, and the rarity of the
records of the species being noted in cases of Fungus-poisoning. In the
books you will see plenty of species suspected of poisonous properties,
from their acrid taste (when uncooked), or from their affinity to
poisonous species, or from their disagreeable smell; these you will do
well to avoid, but you must not condemn them all as uneatable until
more is known about them—a knowledge to be gained only by rash
experimenters.
To take the poisonous Fungi in their usual order, beginning with the
genus Agaricus, the sub-genus Amanita undoubtedly includes several
species. Of course A. muscarius stands first in this category, but we
have heard enough about it, The splendid A. caesareus, which is