268 BARKS 



Allied Drugs. Cuprea Bark ; the bark of Remijia pedunculata, 

 Triana, and R. purdieana, Triana (N.O. Rubiacece, Columbia) ; coppery 

 red, dense, very hard and breaks with a short granular fracture ; 

 contains quinine, cupreine, quinidine, cinchonine, and cinchonamine ; 

 not now in commerce. 



Various species of Cascarilla, Exostemma and Stenostcma ; these 

 barks contain none of the cinchona alkaloids. 



ALSTONIA 

 (Alstonia, Dita Bark) 



Source, &C. The official alstonia bark may be obtained either 

 from Alstonia scholaris, Robert Brown (N.O. Apocynacece) , a tree 

 indigenous to India and the Philippine Islands or from A. constricta, 

 P. Mueller, a native of Australia ; the latter bark is also known as 

 Australian fever bark. The former is the variety usually found in 

 commerce. 



Description. Alstonia scholaris. This bark, also known as dita 

 bark, occurs in single quills or in irregular curved pieces of varying 

 size and appearance. That from older stems or branches is commonly 

 in small, curved or channelled pieces, or quills, and is of a light, 

 yellowish brown colour, rough, irregularly fissured, and spongy exter- 

 nally ; internally it is darker. Such pieces break with a short fracture, 

 the section exhibiting a narrow inner portion (cortex and secondary 

 bast) traversed by numerous, fine medullary rays and a spongy outer 

 portion (cork) of varying thickness. The bark from young branches 

 bears scattered, pale lenticels and is very fibrous. Both kinds con- 

 tain numerous, pitted, sclerenchymatous cells, laticiferous vessels, 

 and prismatic crystals of calcium oxalate, but the young bark contains 

 abundant pericyclic fibres which are seldom visible in old bark. Taste 

 bitter, no odour. 



Alstonia constricta. The bark is in quills or channelled pieces, 

 often of considerable size. Outer surface brown or yellowish brown 

 in colour and deeply fissured both longitudinally and transversely ; 

 inner surface cinnamon brown in colour and deeply striated. The 

 transverse section exhibits an abundant, dark brown cork, within 

 which is a yellowish brown secondary bast. The latter exhibits 

 under the microscope abundant bast fibres in tangentially arranged 

 groups. The taste is very bitter. The aqueous infusion is yellowish 

 and shows a well marked blue fluorescence. 



Constituents. Alstonia scholaris. The chief constituents are the 

 alkaloids ditamine (bitter, crystalline powder), echitenine (amorphous, 

 bitter powder) and echitamine or ditaine. The bark also contains 

 echicerin (crystalline, non-nitrogenous), echicaoutchin (resembles 



