PETROLEUM. — Petroleum (rock-oil, coal-oil, mineral oil) is found in various regions of the world. In the natural state it varies in color from a light green or red to black, more rarely clear. It has a distinctive odor. Some specimens have a very offensive odor due to the pres ence of numerous sulphur and phos phorus compounds. Barbadocs tar, Sen eca oil and Rangoon oil are thick varie ties. The Rangoon oil contains a larger proportion of both the olefin and the benzol series than American oil. Petro leum does not saponify. It is soluble in fixed and volatile oils and in ether, in 64 parts of boiling absolute alcohol, but is nearly insoluble in water and in chloro form. It is a solvent for India-rubber and many resins. By fractional distilla tion and purification it yields a variety of commercial products, the lighter oils being useful as solvents, the heavier be ing used for light, fuel, and lubrication.
All that portion which distills over at or below 122° F. is designated benzene, or naphtha. Hydrocarbons of greater volatility are obtained from naphtha by repeated fractional distillation. Rhigo lene is obtained by distillation from naphtha, distilling over at 64.5° F.
By distilling off the lighter and more volatile portions of American petroleum and purifying the residue, petrolatum, or petroleum-jelly, is obtained. Petro latum is an amorphous pale-yellow to white, odorless, tasteless, or nearly so, transparent, fatty substance, more or less fluorescent. Petrolatum is sold as cos molin, vaselin, albolene, etc. It does not become rancid, and is in most cases a valuable substitute for lard in the prep aration of ointments. It Gan also be ob tained as a semiliquid or liquid oil.
Preparations and Doses. — Petroleum (rock-oil), crude, 1 drachm; refined, 10 to 30 drops.
Petrolatum liquidum, U. S. P. (liquid petrolatum).
Petrolatum molle, U. S. P. (soft petro latum).
Petroleum spissum, U. S. P. (hard petrolatum; consistency of a cerate).
Benzinum, U. S. P. (petroleum-ether, or petroleum-benzin), 10 to 30 minims, in mucilage or capsule.
Rhigolenum (rhigolene; used in spray for local anaesthesia and thermocautery).
Physiological Action. — Petroleum when taken internally in small doses is stimulant, antispasmodic, diaphoretic, antiseptic, and expectorant. It disin
fects the gastro-intestinal and respiratory tracts. In large doses it gives rise to headache, vertigo, pain in the stomach, palpitation of the heart, vomiting, and tetanic spasm.
Poisoning by Petroleum.—In poison ous doses it produces a burning sensation throughout the alimentary tract. The excreta are covered with oil. The skin becomes cold; the pulse feeble, but regu lar; the respiration sighing, with great thirst and restlessness. Death may occur by collapse from failure of respiration and circulation.
In petroleum poisoning a distinction must be made according as to whether the petroleum-vapor is inhaled or the oil has been rubbed into the skin or has been taken internally. It would appear, according to Lewin's researches, that among workers in petroleum-springs no ill effect is produced; that is, as long as the vapor is inhaled in the open air; but in factories similar symptoms are pro duced as by ordinary gas. A feeling of exhilaration is first induced, then heavi ness in the head, vertigo, loss of con sciousness, or anesthetic sleep. Cyano sis, contracted pupils, and vomiting may occur. Once a fatal result was seen. Chronic bronchitis with anmmia may appear after long exposure to the vapor.
Petroleum applied to the skin may in duce moderately serious symptoms. A diffuse inflammation of the cutis may occur in severe cases. When petroleum has been taken internally the symptoms have not always been in proportion to the amount taken. There are two sets of symptoms: (1) gastrointestinal, the kidneys being also involved; and (2) nervous. In the former ease there is vomiting as well as the local irritation in the mouth and gullet. Diarrhoea, with colic, may supervene. In the cere bral form there is headache, anxiety, vertigo, and the pulse is small and in frequent; collapse may occur. Tetanic convulsions have been seen. A marked petroleum-smell has been noted in the sweat and also in the urine, which may sometimes smell of violets. The urine may also contain albumin and formed elements. Johanessen (Berl. klin. Woch., Apr. 20, 27, '96).