402 CONSIDERATION OF CARBON COMPOUNDS. 



form ; it fuses at 98 C. (208 F.). A fragment of cocaine placed 

 on the tongue causes the sensation of numbness without acrid or 

 bitter taste ; the solution in water is faintly bitter. 



Cocaine heated with acids in sealed tubes is decomposed into methyl alcohol, 

 benzoic acid, and ecgonine, showing it to be methyl-benzoyl-ecgonine : 



C 12 H 21 N0 4 + 2H 2 = CH 3 HO + C 7 H 5 CO 2 H + C 9 H 15 NO 3 . 

 Cocaine. Methyl alcohol. Benzoic acid. Ecgonine. 



Ecgonine is found in the coca leaves as benzoyl-ecgonine, C 9 H 15 (C 7 H 5 0)NO 3 

 + 4H 2 O ; this is a white, crystalline substance from which cocaine may be 

 obtained by heating it with methyl-iodide. The mother-liquors obtained in 

 the manufacture of cocaine from the leaves contain the alkaloid in an amor- 

 phous state and possibly one or two other alkaloids, one of which has been 

 named hygrine. Whether these alkaloids are contained in the coca-plant, or 

 are products of the decomposition of cocaine, are questions not yet decided. 



Of the various salts of cocaine, the hydrochlorate, C 17 H 21 NO 4 . 

 HC1, has been used chiefly. This salt crystallizes from alcohol in 

 short, anhydrous prisms, from an aqueous solution, however, with 

 two molecules of water, which are completely expelled at a temper- 

 ature of 100 C. (212 F.). The anhydrous salt fuses at 193 C. 

 (379 F.) and is readily soluble in water ; this salt solution has a 

 somewhat more bitter taste than the alkaloid itself. 



Analytical reactions : 



1. Cocaine salts are precipitated from an aqueous solution as fol- 

 lows : Platinum chloride produces a yellowish-white, mercuric chlo- 

 ride a white flocculent, picric acid a yellow pulverulent, the alkali 

 carbonates and hydroxides a white precipitate, which latter is soluble 

 in ammonia. 



2. To a freshly prepared solution of potassium ferricyanide add 

 an equivalent amount of ferric chloride; with this solution of ferric 

 ferricyanide moisten a slip of filter-paper and place on this a drop of 

 cocaine solution. A deep-blue spot of ferric ferrocyanide will appear 

 shortly in consequence of the deoxidizing action of the alkaloid upon 

 the ferricyanide. (Morphine, a few other alkaloids, and many re- 

 ducing agents show the same reaction.) 



3. Boil a small quantity of cocaine solution for a few minutes with 

 dilute sulphuric acid; neutralize carefully with potassium hydroxide 

 and then add a few drops of ferric chloride solution. A pale brownish- 

 yellow precipitate of basic ferric benzoate will form. 



Aconitine, C 33 H 45 N0 12 ? This alkaloid is found in various species of aco- 

 nitum to the amount of about 0.2 per cent. The commercial article is most 

 likely a mixture of aconitine with other substances, as it is extremely difficult 



