40 ERYTHROXYLON COCA 



prepared the leaves are unbroken, of a fine green colour, and 

 a delicate agreeable somewhat aromatic odour, which is at once 

 perceptible when they are bruised, and which has been compnr. .1 

 to the combined odour of hay and chocolate; but specimens 

 are often met with in which the green colour is replaced by 

 brownish, yellowish- or reddish-brown tints, and the odour lost or 

 of a more or less disagreeable character. Coca when fresh has a 

 somewhat aromatic and slightly bitter taste ; and when carefully 

 dried it has a similar flavour ; but in other cases its aroma is lost, 

 and it is simply bitter and disagreeable. Coca of commerce varies 

 very much indeed in quality. 



Coca has been analysed by Niemann, Stanislas Martin, Maisch, 

 Lossen, Woehler, and other chemists ; and the results of their 

 investigations show that its principal constituents are, a crys- 

 talline alkaloid called cocaine, a volatile odoriferous alkaloid 

 named hygrine, coca-tannic acid and coca-wax. Cocaine is 

 described as crystallizing in small colourless inodorous prisms, 

 having a slightly bitter taste ; sparingly soluble in water, more 

 soluble in alcohol, and still more so in ether ; it is strongly 

 alkaline, and in most of its reactions is said to resemble atropia. 

 When heated with strong hydrochloric acid it is resolved into 

 a new alkaloid ecgonine, together with methyl alcohol, and benzoic 

 acid. Hygrine at ordinary temperatures is a thick oily liquid 

 of a yellowish colour, dissolving readily in alcohol and ether, 

 but only partially soluble in water. " It possesses a strong 

 alkaline reaction, a burning taste, and an odour of trimethylamin." 

 The medicinal properties of coca would appear to depend essen- 

 tially on cocaine and hygrine. Both these alkaloids seem to be 

 in combination with one or more acids ; probably the variety of 

 tannic acid already mentioned, as the addition of lime or other 

 alkali is said to increase to a great extent the flavour and 

 activity of the drug. This latter fact has a very important 

 bearing on the preparations of coca; as those obtained by the 

 agency of milk of lime would thus appear to be more active than 

 simple infusions or extracts of the drug ; the latter are, however, 

 frequently used. 



