Tobacco. Nicotiana tabacum.
Tobacco. Tabacum. U. S. 1890. Nicotiana Tabacum L.—The Virginia tobacco plant is an annual with a large, fibrous root, and an erect, round, hairy, viscid stem, which branches near the top, and rises from three to six feet in height. The leaves are numerous, alternate, sessile, and somewhat decurrent, very large, ovate-lanceolate, pointed, entire, slightly viscid, of a pale green color, and have a narcotic odor. The seeds, examined by F. M. Brandt, yielded no narcotic principle, though a protein-like substance contained in them was thought by its decomposition to produce nicotine. (Neues, Jahrb. fur Pharm., xxi, 42.) William Procter also failed to find nicotine in the seeds, (Proc, A, Ph. A., 1858, 296.)
There is good reason to believe that this plant is a native of tropical America, where it was found by the Spaniards upon their arrival. It is at present cultivated in most parts of the world, and nowhere more abundantly than within the limits of the United States. Virginia is, perhaps, the region most celebrated for its culture. The young shoots, produced from seeds thickly sown in beds, are transplanted into the fields during the month of May, and set in rows with an interval of three or four feet between the plants. Through the whole period of its growth the crop requires constant attention. The development of the leaves is promoted by removing the top of each plant and thus preventing it from running into flower and seed. The harvest is in August. The ripe plants, having been cut off above their roots, are dried under cover, and then stripped of their leaves, which are tied in bundles and packed in hogsheads. While hung up in the drying houses, they undergo a curing process, consisting in exposure to a considerable degree of heat, through which they become moist, or, in other words, are said to sweat, after which they are dried for packing.
Other species also of Nicotiana are said to be cultivated, especially N. rustica L., which yields the Turkish tobacco and is said to have been the first introduced into Europe, and is thought to have been cultivated by the aborigines of this country, as it is naturalized near the borders of some 6f our small Northern lakes. The N. quadrivalvis of Pursh affords tobacco to the Indians of the Missouri and Columbia Kivers; and N. fruticosa, a native of China, was probably cultivated in Asia before the discovery of this continent by Columbus. Besides these there are N. Persica L., cultivated in Persia, and is the source of Persian tobacco; N. repanda Willd., cultivated in Central and Southern North America; N. Bigelovii Wats., of North America. It is very doubtful, however, whether these plants furnish any large part of the commercial tobacco. Latakia tobacco seems to be the product of the N. Tabacum, and Senator Vidal asserts that N. repanda is not found in Cuba, N. Tabacum being the only species there cultivated. (P. J., viii, 710.) Again, the Persian and Turkish tobacco sold under the name of tumbeki, which has been variously attributed toN. Persica and to N. rustica, is in all probability the product of N. Tabacum. [Kew Bulletin, April, 1891.)
The total annual production of tobacco throughout the world at present is estimated at 1,000,000 tons, of which Asia furnishes 350,000, America 300,000, Europe 250,000, and the rest of the world 100,000 tons. (Zeit. fur Angew. Chem., 1905, p. 1623.)
Tobacco, as it occurs in commerce, is of a yellowish-brown color, a strong narcotic penetrating odor which is wanting in the fresh leaves, and a bitter, nauseous, and acrid taste. These properties are imparted to water and alcohol. They are injured by long boiling, and the extract is, therefore, relatively feeble. An elaborate analysis of tobacco was made by Vauquelin, who discovered in it among other ingredients, an acrid, volatile, colorless liquid, slightly soluble in water, very soluble in alcohol, and supposed to be the active principle. It was separated by a complicated process, of which, however, the most important step was the distillation of tobacco juice with potassium hydroxide. In the results of this distillation Vauquelin recognized alkaline properties, which he ascribed to ammonia, but which were, in part at least, dependent upon the acrid principle above mentioned. To this principle the name of nicotine was given; but its alkalinity was ascertained by two German chemists, Posselt and Reimann. The nicotine obtained by Vauquelin and by Posselt and Reimann was a colorless, volatile liquid, and, as subsequently ascertained by Henry and Boutron, was in fact an aqueous solution of the alkaline principle in connection with ammonia. It was reserved for these chemists to obtain nicotine in a state of purity. It exists in tobacco combined with an acid in excess, and in this state is not volatile. It is easily extracted from tobacco by means of alcohol or water as a malate, from which the alkaloid can be separated by shaking it with caustic soda solution and ether. The ether is then expelled by warming the liquid, which finally has to be mixed with slaked lime and distilled in a stream of hydrogen, when the nicotine begins to come over at about 200° C. (392° F.). The percentage of nicotine in tobacco varies considerably—from 1.62 per cent. in Havana tobacco and 2 per cent. in Maryland tobacco to 6 per cent. in Virginia tobacco and 8 per cent. in Kentucky tobacco. For a mode of estimating the proportion of nicotine in tobacco, see Harrison and Self, P. J., June 1, 1912. For an analysis of the ashes of Virginia tobacco, by McD. Irby, of New Orleans, and J. A. Cabell, of Virginia, see Chem. News (Sept. 4, 1874, 117). For Liecke's and Schloessing's methods of estimating nicotine, see 17th edition, U. S. D., p. 1346. For Kosutany's method, see Z. An. Chem., 1893, 277.
Nicotine. (Nicotina or Nicotia.) β-pyridyl-a-n-methyl-pymolidine.—This is a colorless or nearly colorless fluid, of the sp. gr. 1.027, boiling at 247° C. (476.6° F.), and not solidifying at -10° C. (14° F.); having a faint odor when cold; of an exceedingly acrid, burning taste, even when largely diluted; entirely volatilizable, and, in the state of vapor, very irritant to the nostrils, with an odor recalling that of tobacco; inflammable; very soluble in water, alcohol, ether, the fixed oils, and oil of turpentine; strongly alkaline in its reaction, and capable of forming crystallizable salts with the acids. These salts are deliquescent, having a burning and acrid taste, and, like the salts of ammonia, lose a portion of their base by heat. While nicotine has not been prepared synthetically as yet, two isomeric bases, isonicotine and nicotidine, have been prepared. On treatment with oxidizing agents, nicotine yields nicotinic or β-pyridinecarboxylic acid, C5H4N.COOH. In its action on the animal system it is one of the most virulent poisons known. A drop of it, in the state of concentrated solution, is sufficient to destroy a dog, and small birds perish at the approach of a tube containing it. Tannin forms with it a compound of but slight solubility, and might be employed as an antidote. Nicotine exists in tobacco in small proportion; it has been found in the seeds, and, in very small proportion, in the root. There can be little doubt that tobacco owes its activity to this alkaloid, which has also been criminally employed as a poison. (N. Y. Jour. of Med., N. S., ix.) Nicotine has the remarkable property of resisting decomposition amid the decaying tissues of the body, and was detected by Orfila in the bodies of animals destroyed by it two or three months after their death. Mayor concluded from his experiments that nicotine is the active principle in all parts of the plant both before and after curing. (Proc. A. Ph. A., 1865.)
Although Thorns (A. J. P., 1900, p. 227) was unable to detect any nicotine in tobacco smoke, there is no room for doubt that it is present in sufficient amount to be injurious. Lehmann (P. J., Sept. 18, 1909) finds that about 95 per cent. of the nicotine in tobacco passes over into the smoke, and Toth (Chem. Ztg., 1909, p. 866) has shown that the large proportion of nicotine exists in the smoke in uncombined state.
When distilled at a temperature above that of boiling water, tobacco affords an empyreumatic oil, which Brodie proved to be a most virulent poison. It was official in the U. S. P., 1870, under the name of Oleum Tabaci: Oil of Tobacco. A single drop, injected into the rectum of a cat, occasioned death in about five minutes, and double the quantity, administered in the same manner to a dog, was followed by the same result. This oil is of a dark brown color and an acrid taste, and has a very disagreeable odor exactly resembling that of tobacco pipes which have been much used. It has been stated to contain nicotine. (Ann. Ch. Phys., 3e ser., ix, 465.)
It is quite certain that tobacco leaves undergo considerable chemical changes during the processes of curing and preparation for use. Thus, the characteristic odor of ordinary tobacco is entirely different from that of the fresh leaves, and must be owing to the generation of a new volatile principle. The proportion of nicotine is probably slightly diminished by the process of "curing." (See Mayer, Proc. A. Ph. A., 1865.)
Medicinal Properties and Uses.—Tobacco is locally irritant. Snuffed up the nostrils, it excites violent sneezing, and a copious secretion of mucus; chewed, it irritates the mucous membrane of the mouth and increases the flow of saliva; when injected into the rectum, it sometimes operates as a cathartic; and the alkaloid nicotine injected into the cellular tissue of animals evidently produces much pain. In large doses, or in persons unaccustomed to it, tobacco produces severe nausea, sometimes vomiting, accompanied with profuse perspiration, and great muscular weakness. The alkaloid nicotine is a virulent poison. It primarily excites, and secondarily paralyzes, the ganglia upon the sympathetic nerves, stimulates the intestinal muscles, and, in sufficient quantities, has a paralytic action upon the motor nerves. As a result of its action upon the sympathetic ganglia, it causes contraction of the blood-vessels with marked increase in the blood pressure, followed, after large doses, with vascular dilatation and fall, of pressure. The pulse rate is at first decreased, later becomes rapid. There is primary increase in the secretion of the salivary and probably of the other glands, followed, after large doses, by paralysis of secretions.
The use of tobacco was adopted by the Spaniards from the American Indians. In the year 1560 it was introduced into France by the ambassador of that country at the court of Lisbon, whose name—Nicot—has been perpetuated in the generic title of the plant. Sir Walter Raleigh is said to have introduced the practice of smoking into England. In the various modes of smoking, chewing, and snuffing, the drug is now largely consumed in every country on the globe. It must have properties peculiarly adapted to the propensities of our nature to have thus surmounted the first repugnance to its odor and taste and to have become the passion of so many millions. Whether or not nicotine plays any part in the pleasurable effects of tobacco is, despite considerable research and discussion, unsettled, but it is generally agreed that the evil effects of excessive indulgence are due to this alkaloid. The most important disturbances produced are in the digestive and circulatory organs. As a result of the disturbed innervation of the heart, palpitation and cardiac irregularities are common, and the vascular contraction is generally regarded as one of the causes of arterial degenerations.
Formerly much used as a relaxant, tobacco has been superseded by safer and more efficacious remedies, so that it is at present never employed in medicine, except occasionally in chronic asthma. It should always be borne in mind that it's active principle is absorbed readily by the skin, and that serious or even fatal poisoning may result from its too free application to the surface of the body. A case of death is on record, occurring in a child eight years old, in consequence of the application of the expressed juice of the leaves to the head, for the cure of tinea capitis. Death has also been produced by the inhalation of the smoke.
From five to six grains (0.32-0.4 Gm.) of powdered tobacco will generally act as an emetic; but should never be used for this purpose.