784 TOBACCO in the dried leaves varies from less than 2 pur cent, in Havana to nearly 8 per cent, in tobacco produced in the department of Lot in France. The occurrence of nicotia in tobacco smoke is asserted by some chemists, while oth- ers have failed to detect it. Another constitu- ent is tobacco camphor, or nicotianine, a con- crete volatile oil which appears on the surface of the distillate as minute crystals when the leaves are distilled with water; very discrep- ant accounts are given of its sensible proper- ties, which have not been sufficiently studied. Besides these the leaves contain a bitter extrac- tive matter, gum, malate of lime, chlorophyl, albuminoids, malic acid, woody fibre, and va- rious salts. The amount of ash is very large, varying from 16 to 27 per cent. Wolff found in 1,000 parts of air-dried leaves 197'5 of ash, composed as follows: potash, 54-1; soda, 7*3; magnesia, 20'7; lime, 73'1; phosphoric acid, 7*1; sulphuric acid, 7'7 ; silica, 19'0; chlorine, 8 '8. The leaves contain from 2 to 4^- per cent, of nitrogen, partly in the form of nitrates ; this, with the large content of potash and phos- phoric acid, shows the heavy draft made by the crop upon the fertility of the soil, which can only be maintained by the most liberal manuring. By dry or destructive distillation at a red heat, an empyreumatic oil is obtained, of about the color and consistence of molasses, with acrid taste, and precisely the odor of an old pipe ; this is powerfully poisonous ; under the name of oil of tobacco it is used in oint- ments for skin diseases. This oil has been de- tected in tobacco smoke together with nico- tianine (as some assert), nicotia, salts of ammo- nia, hydrocyanic acid, sulphuretted hydrogen, several volatile fatty acids, phenol, creosote, and numerous basic substances of the picolinic series. It appears therefore that the physio- logical effects of smoking cannot be directly deduced from, although closely allied to, those of tobacco administered by the mouth or oth- erwise. The admixture of some of the ma- terials used in the processes of manufacturing tobacco cannot be properly called adultera- tions, as they are added to suit the tastes of consumers. Water, necessary to bring the leaf into proper form, may be sometimes fraudulently used to increase the weight, and those who keep the unmanufactured tobacco in store are careful that it shall not lose in this respect; the other additions, of various saccharine and saline matters, have already been mentioned. In England, where tobacco bears a high price, there is a temptation to add other materials, and, especially in cut tobaccos, various vegetable substances have been de- tected ; dock, rhubarb, coltsfoot, and other leaves, malt sprouts, and peat are among the most important ; but the use of these is not frequent, as detection in the adulteration of tobacco, and even their possession by a tobac- conist, are punished by a fine of 200. The microscope serves for the detection of these adulterations, the structure of the true leaf being quite distinct from that of any likely to be mixed with it. The various salts, such as nitrates to increase the combustibility, and oth- ers to modify the flavor or to increase the weight, are detected by chemical tests. Snuff is more liable to adulteration than any other form of tobacco ; common salt is a very fre- quent addition; ochres and other earthy mat- ters, pearlash to absorb moisture, oxide of lead, and various other foreign substances, including powdered glass (supposed to be accidental), have been detected. The medicinal effects of tobacco upon the system are very marked, whether it is taken internally or applied ex- ternally. In small quantities, taken by either of the methods in which it is commonly used, as smoking, chewing, or snuffing the pulver- ized dry leaf, it acts as a sedative narcotic ; in larger quantities, or with those unaccus- tomed to it, it causes giddiness, faintness, nau- sea, vomiting, and purging, with great debility; as the nausea continues with severe retching, the skin becomes cold and clammy, the mus- cles relaxed, the pulse feeble, and fainting and sometimes convulsions ensue, terminating in death. Its power of causing relaxation of the muscular system is great, and has been taken advantage of in surgical treatment, as by Dr. Physick in a case of obstinate and long con- tinued dislocation of the jaw, the desired effect being produced by smoking, to which the pa- tient was unaccustomed. An infusion or the smoke of tobacco has been introduced into the rectum to facilitate the reduction of a hernia or intestinal obstruction ; but it is now entirely superseded for these purposes by the more ef- fectual and less dangerous ether or chloroform. Its physiological action is nearly opposed to that of strychnia, to which it has been used as an antidote. It is also applied in the form of infusions and cataplasms to relieve various spasmodic affections, and its use generally in medicine is in external applications, the nau- sea it occasions almost wholly preventing its exhibition internally. It is recommended in articular gout, rheumatism, and neuralgia; and the toothache is often relieved by smoking a cigar. The application of the infusion, or even of the leaves, or of powdered tobacco, to sur- faces deprived of the cuticle, has sometimes been attended with fatal effects; these have even followed the inhalation of the smoke. The powerfully nauseating effects of tobacco suggest its use as an emetic, but it is rarely resorted to for this purpose. Entirely differ- ent opinions have been entertained by the most respectable medical authorities as to the effects of tobacco upon the system, whether beneficial or hurtful, as it is commonly used ; and ever since its early introduction many have ear- nestly condemned it for its supposed univer- sally injurious qualities. Its use nevertheless has been constantly increasing, and multitudes among all nations depend upon it daily, suffer- ing extremely if deprived of it for a time. At- tempts have been made to show that the use
