26 LEAVES 



improving the coca, and is not an adulteration. The pale, reddish 

 brown fruits of the coca are also occasionally to be found. 



The plant that yields this variety of coca has been distinguished 

 as E. truxillense, Rusby. 



Java coca is exported in the form of coarse powder ; it does not 

 reach the English market, but is used in Holland and Germany for 

 the extraction of cocaine. 



The student should observe in both Bolivian and Peruvian coca 

 leaves : 



(a) The curved lines on the under surface of the leaf, 



(b) The minute horny apiculus, 



(c) The characteristic odour and taste ; 



in the Bolivian leaves : 



(d) The brownish green colour, prominent veinlets, and less 



broken appearance, 



(e) The ridge above the midrib ; 



in the Peruvian leaves : 



(/) The pale green colour, broken appearance, and less prominent 



veinlets, 

 (g) The absence of a distinct ridge over the midrib. 



Constituents. Coca leaves contain several alkaloids, the most 

 important of which is cocaine, C 17 H 21 N0 4 , which forms colourless 

 monoclinic prisms with a bitter, benumbing taste. Bolivian leaves 

 contain more of this alkaloid than the Peruvian, but the quantity 

 is usually less than 1 per cent. Other alkaloids of less importance 

 are cinnamyl-cocaine and a- and /3-truxilline (isotropylcocaine, 

 cocamine, isococamine) ; these are frequently present in Peruvian 

 leaves in larger quantities than cocaine. All these alkaloids are 

 easily hydrolysed, and they all yield, together with other products, 

 a crystalline alkaloid, ecgonine, from which by suitable treatment 

 cocaine can be regenerated. Thus cocaine, when hydrolysed, yields 

 methyl alcohol, benzoic acid, and ecgonine ; cinnamyl-cocaine yields 

 methyl alcohol, cinnamic acid, and ecgonine ; and truxilline yields 

 methyl alcohol, truxillic acid, and ecgonine. Ecgonine is very closely 

 allied to tropine ; a-truxilline is a powerful heart-poison. (See under 

 * Belladonna-Leaves.') 



In leaves imported from Java benzoyl-pseudotropine or tropa- 

 cocaine has been found ; this alkaloid yields, when hydrolysed, 

 benzoic acid and pseudotropine ; the latter is isomeric with tropine. 

 This variety of coca contains about 0*7 per cent, of total alkaloid ; 

 it also contains four yellow, crystalline glucosides. 



Coca leaves contain, in addition, cocatannic acid. 



Assay. Moisten 5 gm. of the finely powdered leaves with 2 per cent, solution 

 of ammonia ; pack in a long, narrow percolator, percolate with ammoniated 



