The common mushroom, or champignon, (_Agaricus Campestris_) has been long esteemed an article of epicurean delicacy; and is eaten in its fresh state either stewed or boiled; and as a preserve, in the form of pickle or powder. Its juice, moreover, furnishes the sauce so well known by the name of _ketchup_,[463] or _catsup_. _Mr. Miller_ informs us that the true eatable mushroom may be easily distinguished from the poisonous and unpleasant species by the following characters. “When young, it appears of a roundish form, smooth, like a button; which together with its stalk, is white, especially the fleshy part of the button; the gills within, when broken, are livid. As it grows larger, it expands its head by degrees into a flat form; the gills underneath are at first of a pale flesh-colour, but become blackish on standing.” There are besides a vast number of species which may be eaten with perfect impunity; the Agaricus _Procerus_, or tall mushroom, is sometimes exposed for sale in Covent Garden market, and is quite harmless; although, when preserved in pickle, it is very apt to run into the vinous fermentation. With equal safety the Agaricus _Pratensis_, or Scotch bonnet, as it has been called, may be eaten; it occurs in those patches which are well known by the popular name of _fairy rings_. The Agaricus _deliciosus_ is considered by _Withering_ to have been the mushroom which formed the vehicle of poison to _Claudius Cæsar_, as related at page 134 of this volume, and which has been celebrated by the satiric pen of _Juvenal_, and the epigrammatic muse of _Martial_; a species of mushroom, observes _Withering_ which is still highly esteemed in modern Italy, as it was in ancient Rome. _Schæfer_ and _Clusius_, however, consider the plant in question to have been the Agaricus _Xerampelinus_, a species which although esculent, has a strong, and by no means an agreeable flavour. The common champignon has never, as far as we can learn, produced any mischief, although a popular opinion prevails that soil, shade, and other local circumstances, may render it virulent. If any unpleasant symptoms were to follow its ingestion, we should be inclined to regard them as the result of the peculiar idiosyncrasy of the individual, rather than as the consequence of an _absolute_ poison; indeed a question has been raised how far such an explanation may not apply to all the cases of poisoning from this tribe of plants; for it has been observed that in many parts of Europe several of those species of mushroom are eaten with impunity, that are regarded by us as most virulent poisons; of this number we may reckon the Agaricus _Piperatus_, or _Pepper Agaric_, which is eaten in great quantity by the Russians, who fill large vessels with them in the autumn, seasoning or pickling them with salt, and then eating them in the ensuing lent.[464] There is, however, too much direct evidence in favour of the existence of an acrid