578 



MEDICAL BOTANY. 



Fig. 251. 



2. D. contrayerva, Linn. — Caulescent; 

 stem covered with spreading, green, scaly 

 stipules. Leaves palmate ; lobes lanceolate, 

 acuminate, coarsely serrate, and gashed, 

 sometimes almost pinnatifid. Receptacle on 

 a long footstalk, quadrangular, waved or 

 plaited. 



Linn., Mat. Med. 53; Willdenow, 

 Sp. PI. i. 683 ; Jacquin, Amer. iii. 

 614; Lindley, Fl. Med. 300. 



Occurs in Mexico, Peru, the West 

 Indies, &c'. This is the officinal 

 species. 



3. D. drakena, Linn. — Stemless. Leaves 

 cordate, interruptedly pinnatifid, with the 

 segments ovate, entire, acute. Receptacle 

 oval, entire. 



Willdenow, Sp. PI. i. 683 ; Miller, 

 Diet. No. 3 ; Houston, Trans. Roy. 

 Soc; Lindley, Fl. Med. 301. 



Grows in Mexico, in the vicinity of 



Vera Cruz. Lamarck considers it to 



D. contrayerva. be a mere variety of the last, but it 



differs in many essential characters 



from that species. This is much employed in Mexico, and was the source 



of the roots sent by Drake from Peru, to Clusius, who described them in his 



Exotica, 311. 



4. D. houstoni, Miller. — Stemless. Leaves cordate, entire, or palmately angular, 

 acute. Receptacle quadrangular, undulated. 



Miller, Diet. No. 2 ; Willdenow, Sp. PI. i. 682 ; Houston, o. c. ; Lind- 

 ley, Fl. Med. 301. 



Found in high rocky ground in Campeachy, and forms part of the Con- 

 trayerva of commerce. 



The roots of these plants have long been in use in South America and the 

 West Indies under the name of Contrayerva, which means counter-poison. 

 The first account of them is by Clusius from Monardes ; in 1581 he de- 

 scribed another root received from Sir Francis Drake, under the name of 

 Drakena radix, which is supposed to be that of D. drakena. As found in 

 the shops, it consists of prsemorse rhizomes of an inch or two long, rough, 

 hard and scaly, with numerous radicles attached to the lower part. It has a 

 somewhat aromatic odour, and a slight bitterish, warm taste. It yields its 

 properties to alcohol and boiling water. They depend on a Volatile oil, Resin, 

 and Bitter extractive. They evidently are those of D . brasiliensis and not 

 of D. contrayerva, which. Pereira says is not met with in commerce. 



Medical Uses. — Contrayerva is a stimulant tonic and diaphoretic, much 

 resembling Serpentaria in its properties, and by which it has been superseded 

 in practice, being seldom employed in this country. The dose in powder is 

 a scruple to half a drachm. The best form of administration is the infusion. 



Other species have been noticed: thus, Gomez describes D. arifolia, 

 which has the properties of brasiliensis, but is not as active. Descourtilz 

 (Flor. Med. Antill. iv. 105) speaks of D. caulescens of Haiti as having the 

 qualities of Parietaria. 



