CRUDE DRUGS. 



481 



The overground stem is dark or reddish-brown, longitudinally 

 wrinkled and has numerous lenticels and few, somewhat elliptical 

 branch-scars; the bark is about 0.2 mm. thick and somewhat 

 greenish. 



Fig. 208. Transverse section of rhizome of gelsemium: K, cork; C, cortex; WF, wood 

 fibers; T, tracheas; MR, medullary rays; Ph, internal phloem. 



Constituents. — Two alkaloids of great toxicity, the one 

 known as gelsemine, crystallizes in silky needles and on the addi- 

 tion of concentrated nitric acid and heating the solution is colored 

 reddish and then dark green ; the other gelseminine, occurring 

 in amorphous masses and forming yellowish amorphous salts, is 

 colored greenish on the addition of nitric acid. In addition the 



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