A fungus which _bites the tongue_ (20) when tasted would naturally be excluded from our mushroom diet, as would also, of course, those of a _bitter or nauseating taste_; but several species, notably the _Lactarius piperatus_, as its name implies, is very hot and peppery when raw--a characteristic which disappears in cooking, after which it is perfectly esculent. The same applies in a scarcely less degree to the _Agaricus melleus_, and less so to the _Hydnum repandum_ (Plate 27), and other mushrooms. But the poisonous _Russula emetica_ (Plate 13) gives this same hot, warning tang, and this rule (17) would at least thus exclude the harmful species, and is thus contributive to popular safety.
_The salt test_ (21), with that of the silver charm, is also a relic of the dim past, but is absolutely useless as a touchstone. Many poisonous species, notably the Amanita, fail to answer to it. All authorities agree, however, that the addition of salt in cooking, or the preparatory soaking of specimens in brine, has a tendency to render poisonous species innocuous. Indeed, it is claimed that in Russia and elsewhere on the Continent many admittedly poisonous species, even the deadly Fly Amanita, is habitually eaten subsequent to this semi-corning process, by which the poisonous chemical principle is neutralized.
[Sidenote: =Omission of the only true test=]
Among this long list, and many other equally arbitrary and ignorant prejudicial traditions, many of which date back to the earliest times, it is indeed astonishing to note the _conspicuous absence_ of the one and only valuable sign by which the fatal species could be unmistakably determined--a symbol which was reserved for botanical science to discover: the presence of the "_cup_" in the Amanita, which is pointedly emphasized in my Frontispiece, and the importance of which as a botanical and cautionary distinction is considered at more length in the following chapter.
It is well to consider for a moment what is implied in
A fungus may be poisonous in various ways:
2. The cause of violent digestive or other functional disturbance, but not necessarily fatal.
3. The occasion of more or less serious physical derangement through mere indigestibility.