Woe to the fungus epicure who should sample his mushrooms and toadstools on such a criterion as this, as the _most fatal of all mushrooms_, the _Amanita vernus_, would fulfil all these requisites.
_The discoloration of silver_ (8) is a test as old as Pliny at least, a world-wide popular touchstone for the detection of deleterious fungi, but useful only in the fact that it will often exclude a poison not contemplated in the discrimination. On this point, especially as it affords opportunity to emphasize a common disappointment of the mushroom-eater, I quote from a recent work by Julius A. Palmer (see Bibliography, No. 3): "Mushrooms decay very rapidly. In a short time a fair, solid fungus becomes a mass of maggots which eat its tissue until its substance is honey-combed; these cells, on a warm day, are charged with the vapors of decomposition. Now you put such mushrooms as these (and I have seen just such on the markets of Boston and London) over the fire. In boiling, sulphuretted hydrogen or other noxious gases are liberated; you stir with a bright spoon and it is discolored; proud of your test, you throw away your stew. Now this is right, but if from this you conclude that all fungus which discolors silver is poisonous and that which leaves it bright is esculent, you are in dangerous error. It is the same with fish at sea. Tradition says that you must fry a piece of silver with them and throw them away if it discolors. Certainly the experiment does no harm, and shows a decomposition in both cases which might have been detected without the charm." Opposed to this so-called talisman, how grim is the fact that the deadliest of all mushrooms, the Amanita, in its fresh condition, has no effect upon silver.
_The change of color in fracture_ (9) has long been a ban to the fungus as food. But this would exclude several very delicious species, which turn bluish, greenish, and red when broken--viz., _Boletus subtomentosus_ (Plate 22), _Boletus strobilaceus_ (Plate 23), and Lactarius (Plate 18).
_The "toadstools" with "sticky tops"_ thus discriminated against (10) include a number of esculent species, Boleti and Russulæ, and others, as do also the varieties with side-stems (11)--viz., _Agaricus ulmarius_ (Plate 15), _Fistulina hepatica_ (Plate 25), _Agaricus ostreatus_ (Plate 14), etc.