A. Diaphoresis, Dufresnoy.*

Diaphoresis, itching, and burning, 43, 385.

Itching, burning, and tingling, kitzela, 1, 374.

Painful sensations in the skin followed by sweat, 22, 1: 107.

* Des Caracteres, du traitetment et de la cure des dartres .... par l'usage du rhus radicans, etc. Paris, An VII. de la Republiqae. 7

B. "On the eighth day of July, 1795, I applied two or three drops of the milky juice whilst it issued from the common foot-stalk of the leaves of the Rhus Radicans, to the risband of my shirt. These leaves immediately before had been torn from the stalk of the plant by a friend of mine.* My object in applying the juice was to determine in what length of time it would assume the black hue. In a few minutes I found that the linen was stained black, and in a short time after this I observed that the juice had penetrated through the risband, and that it had communicated a dark brown or blackish color to that portion of the epidermis which was immediately under it. The day was unusually warm, and I went into the water to bathe. In the evening I felt a considerable itching of my wrist, and the following morning observed that there were upon it a number of extremely minute vesicles, which contained a fluid more or less limpid or transparent. The itching increased hourly; the wrist and the middle of the forearm began to swell, and the vesicles extended themselves rapidly, chiefly upwards towards the elbow, and partly downwards along the lower part of the wrist, and upon the finger.

"Meanwhile, vesicles accompanied with, and preceded by, itching more or less troublesome made their appearance upon various other parts of the body. The face was universally speckled with them. But these were extremely small, the fluid which they contained was always very limpid, and, without any application except that of cold water every morning, they entirely disappeared in two or three days.

"About the seventh or eighth day, the itching, the inflammation, and the spread of the vesicles appeared to be nearly at their height. At this period, and for some days afterwards, the greater part of the forearm, and about one-third of the arm, were swelled to nearly twice the natural thickness; the itching was intolerable, and the vesicles, in general, were no longer filled with a limpid fluid, but contained a thick matter, or pus, very similar to that of small-pox, and strongly adhering to the linen. On the ninth day, I perceived a swelling in the axillary gland of the right arm, which was that to which the lacteous juice was applied, and which was chiefly af-fected. The swelling rapidly increased until it became of the size of a hen's egg, and on the second day from its appearance it had almost entirely vanished.

"From the period that the swelling was at its height, to its entire disappearance, the itching was almost universal, and much more insupportable than it was before. I attributed this itching to the influence of the poison, which, I suppose, was conveyed into the system from the time that the axillary gland began to swell and inflame. Nevertheless, I could not discover that there was, in consequence of this supposed absorption of the poison, any increase of the number of vesicles upon the surface of the body.

"In fifteen days from the time that the poison was first applied to my arm, all the disagreeable symptoms had ceased; the vesicles had almost disappeared; a desquamation of the affected parts had taken place, and a new epidermis had been formed," 27, p. II., 32.

* "I was not myself within the sphere of action of the plant, which I was careful to avoid, well knowing, from long experience, its injurious effects upon me."

The smoke of the burning wood may produce eruption, 1, 374.

The hand introduced into a vessel filled with the exhalations of the plant was affected with burning, inflammation, and swelling, Van Mons, 36, 4: 406. The emanations are most powerful at night, 3, 1: 720. Dr. Ed. K. Root has personally experienced relapses of the eruption from a single exposure (oral com.). I have witnessed one of these relapses on Dr. R in the month of January, 1880; (H.G.P.).

C. Eczema, pityriasis, Dufresnoy, op. cit.; 86, 2: 126. Psoriasis, Flecthten, 63, 3: 153.

Zoster, pemphigus, eczema, erythema, erysipelas, 2, 283. Eczema, 208; (H.G.P.). Zoster, 208. Hydroa; (H.G.P.). Vesicular affections, 204.

Remarks

The effects of the application of rhus to the skin are so graphically described by Dr. Barton, as observed during the last century, when the plant was comparatively new to science, that I have given his statement in full. Its first therapeutic applications of which we have accounts were made by Dufresnoy, professor of botany at Valenciennes. He was induced to employ it in cutaneous diseases in consequence of the following incident: One day, when lecturing at the botanical garden, a mischievous student said to a young florist who was present, that the professor's account of the noxious properties of rhus was incorrect, as the plant growing in France was perfectly innocent. To convince him of this, he plucked some leaves and rubbed them freely on his hands and wrists, as he knew by previous experience he could do with impunity. The florist, thus persuaded, imitated his example, but in a short time had occasion to regret his imprudence. The next day, finding himself in trouble, he consulted the student, who gravely assured him that he had undoubtedly caught the itch somewhere, and advised him to rub into the affected parts half an ounce of citrine ointment, and to purge himself freely with mercurial pills. This did not mend matters, and, anally, Dufresnoy was made acquainted with the state of affairs. In about ten days the young man recovered from the effects of the rhus, and, to his great surprise, found that a chronic eczema (dartre) of six years' standing, for which he had vainly sought relief, had disappeared at the same time.

The apparent cure of the chronic eruption in this case led Dufresnoy to experiment further with rhus in cutaneous and other affections.

One of the best known, and at the same time most remarkable of the peculiarities of rhus toxicodendron (or R. radicans, as it is sometimes called), 18 the fact that some persons appear to be insusceptible to its poisonous action when applied to the skin, while others are seriously affected by merely passing near and to the leeward of the plant, and without direct contact with it. This led Dufresnoy to inquire whether those who are not affected by its external application are also insusceptible to its therapeutic effects when administered internally. Most writers have assumed that such was the case; but this, I believe, is an error, as I can personally handle both the rhus toxicodendron and the rhus venenata with perfect freedom, and yet am susceptible to the effects of quite small quantities taken internally.*

* See Phililips'Materia Medica, Am. ed., 1870, page 161.

Dr. Barton relates the singular instance of a physician of his acquaintance who could chew the plant with indifference, but in whom a small quantity would produce local inflammation when applied to the skin.

I have used rhus to advantage in several cases of acute eczema internally, and in an anomalous relapsing vesicular affection that might be classed as a case of herpes hydros. I have not employed it externally. Though only semi-officinal in the U. S. Ph. (Fifth dec. revis.), it is found in the German and French Pharmacopoeias, and was contained in the U. S. Pharm. of 1830. The tincture from the fresh plant is the only reliable preparation, that of the German Pharmacopoeia being made from five parts of fresh leaves to six parts of alcohol. The tincture which I have personally employed is made from one part of fresh leaf to two parts of alcohol. Although the active principle of rhus toxicodendron is exceedingly volatile, if the tincture be mixed with either cane or milk-sugar its properties are retained on drying. Owing to the different susceptibilities of individuals to the effects of rhus, no definite dose can be formulated. It is more prudent to commence with an exceedingly small dose and increase it, if necessary. It is a drug that should be administered with extreme circumspection, but when properly employed is of great value.