122 THE USES OF PLANTS. 



yield a valuable purgative, which is obtained as a 

 bitter juice from the fleshy leaves. We import over 

 300 tons of Aloes annually.* Aloes have since 1869 

 formed an article of export from Natal, f 



Xanthorrhcea arborea, R. Br., and X. quadrangulata, 

 F. von Muell., the singular GRASS GUM TREES of 

 Australia, contain abundance of Picric acid, used as 

 a dye and in the preparation of the explosive potas- 

 sium-salt.! 



MELANTHACE.E. 



Veratrum album, L., WHITE HELLEBORE, a native 

 of the mountains of Central and Southern Europe, 

 and V. viride, Aiton, the INDIAN POKE, of North 

 America, contain various alkaloids in their rhizome, 

 which render them purgative, the former drastically 

 so. They are mainly employed in veterinary medi- 

 cine and in the United States. 



Asagrcea officinalis, Lindl. ( = Schxnocaulon, A. 

 Gray =Sabadilla, Brandt), SABADILLA, a native of 

 Mexico, contains Veratria, C 5 2H8 6 N 2 O 15 , useful as an 

 ointment in rheumatism and neuralgia, in its seeds. || 



Colchicum autumnale, L., the MEADOW SAFFRON or 

 AUTUMNAL CROCUS, the resemblance of which to 

 the true Saffron Crocus is merely superficial, is a 

 native of British limestone pastures, which has long 



* ' Pharmacographia,' pp. 616-27 ; Bentley and Trimen, iv, 

 pi. 282-4. 



t Spon, < Encyl. Indust. Arts.' 



!t Smith, ' Domestic Botany,' p. 160. 



* Pharmacographia, pp. 630-3 ; Bentley and Trimen, iv, pi. 

 285-6. 



|| Ibid., p. 633; ibid., iv, pi. 287. 



