FUNGI 531 daces a terribly disgusting and fatal gangre- nous disease^ Pickling and salting renders many fungi innocuous. Agaricus muscarius is one of the most injurious ; yet it is used as a means of intoxication by the Kamtchat- dales. One or two of them are sufficient to produce a slight intoxication, which is peculiar in its char- acter. It stimulates the muscular powers, and greatly excites the nervous system, leading the partakers into the most ridicu- lous extravagances. The only fungus used at the present day in medicine is the er- got of rye, sometimes employed in cases of protracted labor. Several others have been used in times past, like the cordy- Agaricus muscarius. ceps Sinensis, a sphse- roid species parasitic on a caterpillar; but these are now thought to be of no value. The lycoperdons or puff- balls have been used as styptics. Some po- ly pori make admirable razor strops when sliced with a sharp knife. Polyporus fomen- tarius and igniarim have for many years furnished the 'punk which is used as tinder, the corky portion being pounded till its com- pact mass of soft, silky fibres becomes loosened and flexible, and is sometimes used to make caps and other articles of clothing. Agari- cus muscarius is used as fly poison. Some fungi are among the greatest pests of the agri- culturist. The rusts, smuts, and bunt of grain are all fungi of the genera uredo, ustilago, and puccinia. Their mycelium penetrates the tis- sues of the plants, destroys their vitality, and bursting through their cuticles covers them with myriads of their orange, brown, yellow, or black spores. They probably induce decay by a chemical influence which they exert on the juices of the infested plant, as well as by their mechanical interference with its organ- ism. It has been a question how their spores are carried into the tissues, where their ear- liest growth is entirely separated from the outer atmosphere. But when we remember their extreme minuteness, we can understand that they may be drawn up with the fluids which enter their roots, or receive them di- rectly into their tissues through the infinity of breathing pores with which the surfaces of the plants they infest are perforated. For many years agriculturists have had a prejudice against the common barberry as being injurious to wheat, and in some states it has been pro- hibited by law from growing near wheat fields. This has been looked upon by botanists as^a whim which had no foundation in fact; but in this case, as in others, popular belief was right although the reason it assigned for the effect' m this case, the pollen of the barberry, was wrong. It is now found that the fungus so common upon the leaves of the barberry is one ol the several forms of the wheat smut. The mildews of the grape and other fruits are my- celoid growths, which in certain stages have been thought to be perfect plants (oidium) from their possessing a power of reproduction. Certain cells take on a vesicular growth filled with a mass of minute bodies which were thought to be the true fruit. But the later observations of Leveille, Tulasne, and others, have shown that these are arrested stages of growth of an entirely different ascigerous ge- nus, erysipJie. These produce their fruit in minute black pustules, from the base of which peculiar radiating processes arise, sometimes of great beauty. The mildews grow on the sur- face of fruits, and injure them more by cho- king up their pores and mechanically confining them with their dense, felty growth, than by abstracting their juices. The potato rot is ac- companied by a rapid growth of the mycelium of botrytis infestans, which penetrates the leaves, stems, and tubers, inducing rapid decay. It ap- pears on the sur- face in the form of a minute white mould. Many other plants are similar- ly affected. Boleti are sometimes trav- ersed by a minute mould, sepedonium chrysospermum, which gives a gold- BoletU8 ^ato. en-yellow hue to the flesh. Dry rot in timber is caused by the penetrating mycelium of merulius lacrymans and polyporus destructor. The black excres- cent growth on plum trees is occasioned by the sphceria morbosa, which covers the warts its mycelium has made with its minute black, compacted perithecia. The fairy rings which in olden times were thought to be the scenes of midnight fairy revels, are produced by the growth of different species of agaricus. As they exhaust the soil by one year's growth, their mycelium pushes into the richer por- tions around; and thus they extend the cir- cle of their growth, furnishing by their decay a manure for the next year's grass, which is darker and denser in consequence. Fungi have been classified in various ways by differ- _nt mycologists. By the early writers they were arranged according to their external ap- pearances ; but as more exact means of obser- vation multiplied, their microscopic structure became better known, and a nearer approach was made to a classification in consonance with their true affinities. From Cffisalpinus in 1583 to Nees von Esenbeck in 1817, the pro-
