Thuja. Thuja occidentalis. Arbor vitae, White cedar.

Thuja. N. F. IV. Arbor Vitae. White Cedar—"The recently dried, leafy young twigs of Thuja occidentalis Linné (Fam. Pinaceae), with stems not over 4 mm. in diameter, and without the presence of more than 1 per cent. of foreign substances." It is specifically characterized by the appressed-imbricated leaves, the pointless cone-scales, and the broad wings extending all around the seeds. It attains a height of 20 m., and grows in swampy grounds from Pennsylvania northward and westward, often forming extensive "cedar swamps." In Canada and the extreme northern parts of the United States it is commonly called white cedar, a name sometimes applied to Chamaecyparis thyoides (L.) B. S. P., which latter is more properly called Southern white cedar. The wood is reddish, soft, fine-grained, and very durable. The leaves, or small twigs invested with the leaves, have an agreeable, balsamic odor, specially when rubbed, and a strong, balsamic, camphoraceous, bitter taste. The twigs are described as "fan-shaped, flattened, bearing the scale-like leaves appressed in four rows; leaves of the edges boat-shaped, the intermediate flat, those at the tips of the twigs very broad, the lower elongated, all bearing conspicuous glands on the back. Odor strongly balsamic, aromatic and pungent; taste camphoraceous, terebinthinate and bitter. Thuja yields not more than 7 per cent. of ash." N. F. A. Kawalier, of Vienna, found in them volatile oil, a bitter principle called pinipicrin, C22H36O11, which occurs also in Pinus sylvestris, sugar, gelatinous matter, a variety of wax, resin, and tannic acid; also a peculiar crystallizable coloring principle, thujin, to which he gives the formula C20H22O12. It is of a citron-yellow color and an astringent taste, soluble in alcohol, inflammable, and when its alcoholic solution is heated with diluted hydrochloric or sulphuric acid it splits up into glucose and thujigenin, C20H22O12 + H2O = C6H12O6 + C14H12O7 and by continuing the reaction another molecule of water is taken up by the latter and thujetin, C14H14O8, is formed. Thujetin is possibly identical with quercetin. When thujin is heated with barium hydroxide, instead of thujetin is obtained another product, thujetic acid, C28H22O13. The same chemist determined that the tannic acid of this plant is identical with pinitannic acid, which he had previously obtained from the leaves of Pinus sylvestris L. (See, for details, Chem. Gas., Nos. 392, 393, 1859.) According to Hubschmann, the leaves and twigs of Thuja occidentalis yield also 1 per cent. of an essential oil of sharp, camphor-like taste, sp. gr. 0.925, boiling point from 190° to 206° C. (374°-402.8° F.), and easily soluble in alcohol. According to Schim. Rep., April, 1897, thuja oil (oil of white cedar) contains pinene, fenchone, thujone, and probably carvone.

F. K. Bailey has reported a case of poisoning in a girl, aged fifteen, who took sixteen drops of the oil of white cedar, and directly afterwards fell unconscious, with clonic spasms followed by epileptiform convulsions lasting at intervals for several hours. Long-continued irritation of the stomach resulted. (N. R., 1872.)

In the form of decoction, thuja has been used in intermittent fever, and, according to Schoepf, in coughs, fevers, scurvy, and rheumatism, and as an emmenagogue. Made into an ointment with lard or other animal fat, the leaves are said to form a useful local application in rheumatic complaints. Sicard and Larue (Gaz. des. Hop., 1909) assert that the injection of the tincture of thuja into warts will cause their rapid disappearance. A yellowish-green volatile oil, which may be obtained from the leaves by distillation, has been used with success in worms. According to Hildebrand both fenchone and thujone act as stimulants to the heart muscle. (A. E. P. P., xlviii.) According to Prochnow (A. I. P. T., xxi, p. 314) the infusion of thuja has a stimulating effect upon the isolated uterus similar to that of hydrastis. The dose of the fluidextract made with alcohol is half a fluidrachm (2 mils) from three to six times a day.

The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.