ly as unfair
to decry the mushroom on account of its low nutritive value, as it is
wrong to attribute to it qualities which are nothing short of absurd in
view of its composition. In some respects its place as a food is not
unlike that of the oyster, celery, berries, and other delicacies. Worked
out on the basis of nutritive value alone they would all be condemned;
the oyster for instance presents a showing but little better than the
mushroom, and vastly inferior, so far as economy is concerned, to the
common potato. This, too, for oysters purchased by the quart. The
nutritive value of one cent's worth of oysters "on the half shell" would
be interesting!

The question of the toxicology of the higher fungi is one of very great
theoretical and practical interest. But on account of the great
difficulties in the way of such investigations comparatively little has
yet been accomplished. A few toxic compounds belonging chiefly to the
class termed alkaloids have, however, been definitely isolated.

=Choline.=--This alkaloid is of wide occurrence in the animal and
vegetable kingdoms. It has been isolated from _Amanita muscaria_, _A.
pantherina_, _Boletus luridus_, and _Helvella esculenta_. It is not very
toxic, but on uniting with oxygen it passes over to muscarine. According
to Kobert the substance formed from choline on the decay of the
mushrooms containing it is not muscarine, but a very closely related
alkaloid, _neurin_. This transformation of a comparatively harmless
alkaloid to an extremely deadly one simply by the partial decay of the
plant in which the former is normally found, emphasizes very much the
wisdom of rejecting for table use all specimens which are not entirely
fresh. This advice applies to all kinds of mushrooms, and to worm-eaten
and otherwise injured, as well as decayed ones. Neurin is almost
identical in its physiological effects with muscarine, which is
described below.

=Muscarine.=--This is the most important because the most dangerous
alkaloid found in the mushrooms. It is most abundant in _Amanita
muscaria_, it is also found in considerable quantity in _Amanita
pantherina_, and to a lesser, but still very dangerous extent in
_Boletus luridus_ and _Russula emetica_. It is quite probably identical
with bulbosine, isolated from _Amanita phalloides_ by Boudier.
_Muscarine_ is an extremely violent poison, .003 to .005 of a gram (.06
grain) being a very dangerous dose for a man. Like other constituents