Cocaïne

"Cocaïne is prepared by digesting coca leaves with 85 per cent. alcohol containing a small quantity of sulphuric acid, mixing the expressed mass with milk of lime, neutralising the filtrate with sulphuric acid, evaporating off the alcohol, mixing the residue with water, precipitating the resulting yellow-brown solution with carbonate of sodium, treating the brown precipitate of impure cocaïne with ether, and evaporating. Cocaïne then remains, partly amorphous, partly crystalline, and may be purified by repeated treatment with alcohol."