Another form under which tobacco is used, is that of _snuff_. The basis of snuff is tobacco powdered; but many other matters are added, to give it a peculiar smell, or to impart pungency to it. When first applied to the nose, snuff excites sneezing, but, by repetition, this entirely ceases. The practice of taking snuff has, in some instances, been found injurious to the smell and the voice; it has been attended with loss of memory, and by symptoms of a weakened or debilitated state of the nervous system. But there is no mode of using tobacco so disgusting, to persons unaccustomed to it, as chewing. By the labouring classes, and particularly by mariners, this practice is chiefly followed, from a notion, though apparently a very erroneous one, that it will prevent the return of hunger, and, in some degree, supply a lack of food. Though all these are disgusting as practices, there is no doubt, but, medicinally, they may be attended with good effects. By smoking and chewing, tooth-ach has often been relieved; and some persons consider the former a means of guarding against contagion. The occasional and moderate use of snuff has, in several cases, been found beneficial, particularly in head-achs, and in diseases of the eyes and ears. Infusions of tobacco are sometimes administered in medicine, but this drug is principally given in the form of a vinous or watery infusion. Tobacco is a powerful medicine, and requires to be used with great caution. The smoke of this herb, when blown against noxious insects, destroys them, and is the means which gardeners adopt for ridding hot-houses and green-houses of such as infest their plants. The tobacco plant is sufficiently hardy to sustain the rigour of an European climate, and is cultivated in several parts of Spain and Portugal. As however, on importation, it pays a heavy tax to government, the culture of it in this country is restricted, by the legislature, to half a rod of ground in _physic gardens_; and if this be exceeded the cultivator is liable to a penalty of ten pounds for every rod. The different kinds of tobacco and snuff are attributable rather to the difference of climate and soil in which the plants have been grown, and to the different modes of management and manufacture, than to any essential distinction in the plants from which they are manufactured. 66. _DEADLY NIGHTSHADE_ (Atropa belladonna) _is an extremely poisonous plant, which grows in hedges and waste grounds, in several parts of England, and has somewhat oval leaves of dull green colour, purple bell-shaped flowers, and shining black berries, each about the size of a small cherry._