SENEGA 311 



The student should observe 



(a) The prominent keel, 



(b) The irregular wood in transverse sections, 



and should strip the bark from the root and examine the wood. 



Constituents. Senega root contains as principal constituents 

 senegin and polygalic acid. These substances are both glucosides, 

 and resemble, but are not identical with, quillaja-sapotoxin and quillajic 





FIG. 156A. Senega root. A, trans verse section of normally 

 developed root ; B, (7, D, of abnormally developed 

 roots, a, bark ; b, wood ; v, bast. Magnified. (Berg.) 



acid, constituents of quillaja bark, their action being qualitatively 

 the same, but quantitatively different (Atlass, 1890). Polygalic acid 

 is sternutatory, and imparts to water the property of frothing. Senegin 

 is decidedly toxic. Both these bodies require, however, further 

 investigation. 



The drug often contains a small percentage of methyl salicylate (oil 

 of wintergreen) , probably produced by the gradual decomposition 

 of an unknown glucoside ; its presence has been utilised as a test of 

 the identity of the drug, but it is unreliable. Senega root also contains 

 about 5 per cent, of fixed oil, but is free from starch ; it yields about 

 4 per cent, of ash. 



Use. Senega is used as a stimulant expectorant in bronchitis. 



Varieties. Northern senega, collected in the north-western States, 

 is considerably larger than the usual variety (western senega), and 



