6o6 



BOTANY AND PHARMACOGNOSY 



coca leaves contain a volatile aromatic principle ; a tannin giving 

 a green color with ferric salts ; and calcium oxalate. 



Cocaine (benzoyl-methyl-ecgonine) occurs in monoclinic 

 prisms which are sparingly soluble in water, soluble in alcohol. 



Fig. 261. Transverse section of coca leaf near the midrib; U. upper epidermis; P, 

 palisade cells, some of which contain monoclinic prisms of calcium oxalate; M, loose paren- 

 chyma, some of the cells of which also contain monoclinic prisms of calcium oxalate; L, 

 lower epidermis with distinct papillae; CA, monoclinic prism of calcium oxalate, SF, 

 sclerenchymatic fibers; T, traclieae; S, sieve. 



the solution having a bitter taste and producing a characteristic 

 numbness. It forms crystalline salts and yields, on hydrolysis. 

 which is rather easily accomplished, benzoic acid, methyl alcohol 

 and ecgonine. (See Fig. 157, also Part IV.) 



