Many instances are on record of symptoms of poisoning, and even death, having followed the consumption of plants which have passed as true mushrooms ; these cases have probably arisen from the examples consumed being in a state of decay, or from some mistake as to the species eaten. It should always be specially noted whether the fungi to be consumed are in a fresh and whole some condition, otherwise they act as a poison in the same way as any other semi-putrid vegetable. Many instances are on record where mushroom-beds have been invaded by a growth of strange fungi and the true mushrooms have been ousted. When mush rooms are gathered for sale by persons unacquainted with the dif ferent species mistakes are of frequent occurrence. A very com mon spurious mushroom in markets is A. velutinus, a slender, ringless, hollow-stemmed, black-gilled fungus, common in gardens and about dung and stumps; it is about the size of a mushroom, but thinner in all its parts and far more brittle; it has a black hairy fringe hanging round the edge of the cap when fresh. An other spurious mushroom, and equally common in dealers' bas kets, is A. lacrymabundus; this grows in the same positions as the last, and is somewhat fleshier and more like a true mushroom; it has a hollow stem and a slight ring, the gills are black-brown mottled and generally studded with tear-like drops of moisture. In both these species the gills distinctly touch and grow on to the stem. Besides these there are numerous other black-gilled species which find a place in baskets—some species far too small to bear any resemblance to a mushroom, others large and deliquescent, generally belonging to the stump- and dung-borne genus Coprinus. The true mushroom itself is to a great extent a dung-borne species, therefore mushroom-beds are always liable to an invasion from other dung-borne forms.
Sometimes cases of poisoning follow the consumption of what have really appeared to gardeners to be true bed-mushrooms, and to country folks as small horse mushrooms. The case is made more complicated by the fact that these highly poisonous forms now and then appear upon mushroom-beds to the exclusion of the mush rooms. This dangerous counterfeit is A. fastibilis, or sometimes A. crustuliniformis, a close ally if not indeed a mere variety of the first. A description of one will do for both, A. fastibilis being a lit tle the more slender of the two. Both have fleshy caps, whitish, moist and clammy to the touch; instead of a pleasant odour, they have a disagreeable one ; the stems are ringless, or nearly so; and the gills, which are palish-clay-brown, distinctly touch and grow on to the solid or pithy stem. These two fungi usually grow in woods, but sometimes in hedges and in shady places in meadows, or even, as has been said, as invaders on mushroom-beds. The pale clay coloured gills, offensive odour, and clammy or even viscid top are decisive characters. Besides the foregoing the difference in the nature of the attachment of the gills near the stem, the absence of a true ring, and of a pendent frill will be noted. The colour, with
the exception of the gills, is not unlike that of the mushroom. In determining fungi no single character must be relied upon as con clusive, but all the characters must be taken together. Sometimes a beautiful, somewhat slender, fungus peculiar to stumps in woods is mistaken for the mushroom in A. cervinus ; it has a tall, solid, white, ringless stem and somewhat thin brown cap, furnished un derneath with beautiful rose-coloured gills, which are free from the stem as in the mushroom, and which never turn black. It is probably a poisonous plant, belonging, as it does, to a dangerous cohort. Many other species of Agaricus more or less resemble A. campestris, notably some of the plants found under the sub genera Lepiota, V olvaria, Pholiota and Psalliota; but when the characters are noted they may all with a little care be easily dis tinguished from each other. The better plan is to discard at once all fungi which have not been gathered from open pastures ; by this act alone more than nine-tenths of worthless and poisonous species will be excluded.
In cases of poisoning by mushrooms immediate medical advice should be secured. The dangerous principle is a narcotic, and the symptoms are usually great nausea, drowsiness, stupor and pains in the joints. A good palliative is sweet oil; this will allay any corrosive irritation of the throat and stomach, and at the same time cause vomiting.
In Paris mushrooms are cultivated in enormous quantities in dark underground cellars at a depth of from 6o to 16o ft. from the surface. The stable manure is taken into the tortuous passages of these cellars and the spawn introduced from masses of dry dung where it occurs naturally. In France mushroom-growers do not use the compact blocks or bricks of spawn so familiar in Eng land, but much smaller flakes or "leaves" of dry dung in which the spawn or mycelium can be seen. Less manure is used in these cellars than is generally seen in the mushroom-houses of England, and the surface of each bed is covered with about an inch of fine white stony soil. The beds are kept artificially moist by the appli cation of water brought from the surface, and the different galler ies bear crops in succession. As one is exhausted another is in full bearing, so that by a systematic arrangement a single proprietor will send to the surface from 300 lb. to 3,000 lb. of mushrooms per day. The passages sometimes extend over several miles, the beds sometimes occupying over 20 m., and, as there are many proprie tors of cellars, the produce of mushrooms is very large. The mush rooms are not allowed to reach the fully expanded condition, but are gathered in a large button state, the whole growth of the mush room being removed and the hole left in the manure covered with fine earth ; the beds remain in bearing for six or eight months. The equable temperature of these cellars and their freedom from draught is one cause of their great success and to this must be added the use of natural virgin spawn.