The thuja occidentalis, so named by Linnaeus in contradistinction from the Eastern thuja, thuja orientalis, which was brought to Europe from northern China, is found in the West Indies, in the United States, and in Canada. Torrey, in his Elora of the State of New York, furnishes the fol- lowing description of this plant: "A tree with a narrowly conical and tapering head, seldom more than thirty to thirty-five feet high and to twelve inches in diameter, much branched; the ultimate divisions flattened and covered with numerous obtuse shining leaves, each furnished with a little vesicle which (as in white cedar) is filled with a thin aromatic turpentine. Sterile aments minute at the ex- tremity of the branchlets, consisting of a few concave, scale-like anthers. Cones about five lines long, yellowish-brown ; the scales loosely imbricating, opening to the base. Seeds conspicuously winged, emarginate, one under each scale. " Rocky banks of rivers and hill-sides, also in swamps ; abundant and very conspicuous on the Hudson above Newburgh, Oriskany swamp, and various parts of the northern and western counties of the state of New York. The wood is light, of a reddish color and, though soft, is very durable. It is not much used for lumber, as its trunk does not afford pieces of sufficient length. It is often planted about houses and in pleasure grounds. In some parts of the country it is called white cedar, and in New England it is often called hack- mattack." Thuja acts, especially, upon the genito-urinary organs, producing wart-like excrescences which will be fully described hereafter. The remedy affects also the skin and other parts of the body. The following analysis of the action of the remedy, as obtained from the provings of Hahnemann and others, is based upon the ex- haustive article of Dr. Mayrhofer. General. — 1. Thuja stands in an intimate relation to (a.) the genito-urinary system, (b.) to the cutaneous system in all its ramifi- cations. The sexual organs are affected sympathetically. The fibro- serous and mucous membranes bear the stamp of primary effects ; the external skin, of the secondary. 2. The general character of the pathological condition, which THUJA OCCiDENTALIS. 857 thuja sets up in the attacked parts, is that of irritation. This irrita- tion, which may even increase to inflammation, causes in the secret- ing organs (mucous membranes, urinary apparatus and glands) an increased and altered secretion. In the external skin the irritation is concentrated in single spots, and manifests : inflammation, sup- puration, formation of warts and excrescences. 3. The affections of thuja present the following peculiarities : (a.) They attack only a single organ, limb, joint or spot at a time; and these local affections usually cease when morbid symp- toms arise in a different province. (b.) They come on for the most part in abrupt paroxysms, begin suddenly, and end as though they were snapped off. (c.) They make their appearance especially during rest, and either diminish or disappear by movement ; nay, the pains which appear in circumscribed spots often instantaneously disappear on touching the affected spot, and return immediately on quitting the contact. They come on consequently, for the most part, in the evening in bed, and in the morning on waking ; they are aggravated, too, by passing from a cold into a warm temperature, and are diminished by the opposite. The pains in the joints only are aggravated by movement, and violent affections or febrile symptoms remain the same whether in rest or motion. (d.) They more frequently affect the left side of the body, though they do not on that account neglect the right. 4. The most constant kinds of pain which thuja excites in its most extensive sphere of operation in the different organic struc- tures, are : drawing and tension in the limbs and joints, burning in the urinary organs, itching and crawling on the skin. 5. The course of the thuja-sickness is partly acute, partly chronic. The symptoms of the primae via? go off in a short time, but those of the secundge vise run a very irregular course, and are characterized by great mutability and caprice. They return after intervals of hours, days, weeks, continue sometimes shorter and sometimes longer, and appear now in this, now in that part of the body. The cutaneous excrescences, finally, as the concluding products of thuja, are as slow in disappearing as they are in coming, and remain for months. 6. The true attendants of a thuja fever are strongly marked, predominant cold, and gloomy, depraved state of mind. To express the physiological character of the arbor vitse in the shortest manner, 858 THUJA OCCIDENTALIS. it is : exaltation of the cutaneous system, with disposition to dermatic excrescences.