GENTIANA. 293 



ASCLEPIADACE.E. 



II cm i do sin i Radix HEMIDESMUS ROOT. 

 The dried root of Hemidesmus indicus. Imported 

 from India. 



Characters. Yellowish-brown, cylindrical, tortuous, fur- 

 rowed, and with annular cracks, having a fragrant odour, and a 

 very agreeable flavour. 



Substances resembling Hemidesmm : Sarsaparilla, Ipecacu- 

 anha, Senega. Hemidesmus is known by cracks and absence of 

 twisting. 



Composition. The composition of hemidesmus is imper- 

 fectly known. It is believed to contain hemidesmic acid, a 

 volatile crystallisable substance. 



Preparation. 

 Syrupus Hemidesmi. 1 in 8. Dose, 1 to 4 fl.dr. 



ACTION AND USES. 



Hemidesmus is used in India as an alterative in lieu of 

 sarsaparilla, and the same obscurity exists respecting the action 

 and value of this as of the other drug. See Sarsce Radix, p. 35 o. 



GENTIANACEJE. 



Oeiitiaiire Radix GENTIAN ROOT. The dried 

 root of Gentiana lutea. Collected in the mountainous 

 districts of central and southern Europe. 



Characters. From half an inch to one inch in thickness, 

 several inches in length, often twisted, much wrinkled, or 

 marked with close transverse rings ; brown externally, yellow 

 within, tough and spongy ; taste at first sweetish, afterwards 

 very bitter. 



Composition. Gentian contains ! per cent, of an active 

 bitter glucoside, gentiopicrin, C 2o H 3o 12 , which is crystalline, 

 readily soluble in water and dilute spirit, and yields, by 

 decomposition, glucose and gentiogenin. It is united with an 

 inert non-bitter body, gentianic acid* sugar, gum, and a trace 

 of a volatile oil. 



Incompatibles. Sulphate of iron, nitrate of silver, and lead 



, Preparations. 



1. Extracting. Gentianse. Aqueous. Dose, 5 to 10 gr. 



