The rigid utilitarian will hardly be satisfied with the short catalogue which can be furnished of the uses of fungi. Excepting those which are employed more or less for human food, very few are of any practical value in arts or medicine. It is true that imperfect conditions of fungi exert a very important influence on fermentation, and thus become useful; but, unfortunately, fungi have the reputation of being more destructive and offensive than valuable or useful. Notwithstanding that a large number of species have from time to time been enumerated as edible, yet those commonly employed and recognized are very few in number, prejudice in many cases, and fear in others, militating strongly against additions to the number. In Great Britain this is especially the case, and however advisable it may be to exercise great care and caution in experimenting on untried or doubtful species, it can only be regarded as prejudice which prevents good, in fact, excellent, esculent species being more extensively used, instead of allowing them to rot by thousands on the spots where they have grown. Poisonous species are also plentiful, and no golden rule can be established by means of which any one may detect at a glance good from bad, without that kind of knowledge which is applied to the discrimination of species. Yet, after all, the characters of half a dozen good esculent fungi are acquired as easily as the distinctions between half a dozen birds such as any ploughboy can discriminate. The common mushroom (_Agaricus campestris_) is the best known esculent, whether in its uncultivated or in a cultivated state. In Britain many thousands of people, notably the lower classes, will not recognize any other as fit for food, whilst in Italy the same classes have a strong prejudice against this very species.[A] In Vienna, we found by personal experience that, although many others are eaten, it is this which has the most universal preference, yet it appears but sparingly in the markets as compared with others. In Hungary it does not enjoy by any means so good a reputation. In France and in Germany it is a common article of consumption. The different varieties found, as the results of cultivation, present some variation in colour, scaliness of pileus, and other minor features, whilst remaining true to the constituent characters of the species. Although it is not our intention to enumerate here the botanical distinctions of the species to which we may call attention, yet, as mistakes (sometimes fatal) are often being recorded, in which other fungi are confounded with this, we may be permitted a hint or two which should be remembered. The spores are purple, the gills are at first delicate pink, afterwards purple; there is a permanent ring or collar round the stem, and it must _not_ be sought in woods. Many accidents might have been spared had these facts been remembered.