392 MEDICAL BOTANY. 



purpureum, or' Gravel root, and the E. tcucrifolium, or Wild Horehound. The 

 first of these, as its common name indicates, has obtained some celebrity as a 

 diuretic in diseases of the kidneys and bladder, and the latter is spoken of 

 highly as a diaphoretic, diuretic, and tonic, in febrile complaints, by Dr. Jones 

 of Georgia. They do not, however, appear to possess any powers differing 

 from the E. perfoliatum. E. cannabinum of Europe, was at one time in 

 high repute as a deobstruent, but the recent experiments of Deslongchamps 

 and others show that its therapeutic powers are very slight. The E. aya- 

 pana, a native of Brazil, was also considered entitled to a conspicuous rank 

 as an alexipharmic and febrifuge, but ample trials of it have proved that it 

 deserves no higher rank than the other species already mentioned. 



Mikania. — Willdenow. 



Heads mostly 4-flowered. Receptacle naked, narrow. Scales of the involucre 4 — 5* 

 Corolla dilated, or campanulate at the summit, 5-toothed. Anthers partly exserted. Ache' 

 nia angled. Pappus in a single series, capillary, scabrous. 



A genus of shrubby, or herbaceous, and usually climbing plants, mostly 

 peculiar to tropical America, with opposite, commonly cordate leaves, but 

 varying much. Heads corymbose, panicled, or spicate. Flowers whitish. 

 They are very closely allied to Eupatorium, both in their sensible and medi- 

 cinal properties, and would not require notice, were it not that one of the 

 species attracted much attention some years since as a remedy in malignant 

 fevers, cholera, &c. 



M. guaco, Humboldt and Bonpland, — Stem twining, branches terete, sulcate, hairy ; 

 leaves ovate, subacuminate, somewhat narrowed at base, remotely dentate, rough above, 

 hairy beneath ; corymbs axillary, opposite ; flowers subternate, with linear bracteoles ; 

 achenia smooth. 



Humboldt and Bonpland, PI. JSq. ii. 84 ; Kunth, Nov. Gen. Am. iv. 136 ; 

 De Candolle, Prod. iv. 193 ; Lindley, Flor. Med. 452. 

 Common Names. — Guaco ; Huaco. 



Description. — Stem twining. Branches round, sulcate, hairy. Leaves petiolate, ovate, 

 somewhat acuminate, shortly narrowed at base, remotely toothed, reticulate, roughish above, 

 hairy beneath. Corymbs axillary, pedunculate, opposite. Heads somewhat ternate, ses- 

 sile. Bracteoles linear, shorter than the involucre. Involucral scales linear, oblong, ob- 

 tuse, downy. Achenia smooth. 



The part used is the leaves, and it is stated that they should be employed in a 

 fresh state, as desiccation deprives them of much of their power. According 

 to M. Faure, those met with in commerce are usually injured both by want 

 of care in drying them, and by heating during the voyage. This chemist 

 made an analysis of the dried leaves, and found them to contain : a Fatty 

 matter analogous to wax, Chlorophylline, a peculiar Resin, which he calls gua- 

 cine, Extractive and astringent matter analogous to tannin, &c. The guacine, 

 from his account of it, appears to be very analogous to the resinoid substance 

 found in the Eupatorium. The taste of the leaves is bitter, and in a fresh 

 state their odour is strong and disagreeable. 



Medical Properties. — The Guaco has long been known to the natives of South 

 America, and is highly esteemed by them as an antidote against the venom 

 of serpents. For this purpose, the expressed juice of the leaves, or a strong 

 infusion of them, is taken, and the crushed leaves applied to the wound. In 

 corroboration of its good effects in such cases, Mutis states that he has been 

 a personal witness of its curative powers, in the bites of the most venomous 

 species of serpents ; and his testimony is supported by that of Bertrero. To 



