OPIUM ALKALOIDS 271 



chloroform or ether. The microscopic crystals from hot alcoholic 

 solutions vary in length from 0.3 mm. to 2.5 mm. (Fig. 123). 



The following color tests are distinctive for codeine: On heating 

 codeine with concentrated sulphuric acid the solution is colored blue. 

 On the addition of concentrated sulphuric acid containing traces of 

 iron or nitric acid to codeine, the solution becomes green, changing 

 to blue, a blue precipitate finally separating. Dilute solutions of 

 ferric chloride give a blue color with codeine, which is permanent if 

 the solution be gently warmed. Codeine crystals are colored red 

 with nitric acid, the solution remaining colorless or only becoming 

 yellow on heating. On heating a solution of codeine hydrochloride 

 in an autoclave with zinc chloride, an amorphous, yellowish-gray 

 powder is formed, known as apocodeine hydrochloride, and having 

 the same physiological action as apomorphine hydrochloride. 



Some opium obtained from plants cultivated in France yielded 

 2.81 per cent of codeine, while the morphine was but 2.41 per cent 

 and the narcotine 0.10 per cent. 



Narcotine exists in opium to a very large extent as a free base. 

 It is found in greater amount in Persian and Indian opium than in 

 Turkey opium. It forms colorless, shining, rhombic prisms or 

 needles, that are tasteless, insoluble in water, but soluble in alcohol. 

 With concentrated sulphuric acid narcotine is colored greenish-yellow, 

 the solution on heating changing to red and finally violet. It may 

 be converted into a number of compounds, of which hydrocotarnine 

 and vanillin are probably the most interesting. 



At about 15 C. one part of narcotine is soluble in 100 parts of 

 alcohol (85 per cent); 166 parts of ether; 2.7 parts of chloroform, 

 and 22 parts of benzene. One part of narcotine is soluble in about 

 7000 parts of boiling water. Narcotine is a feeble base and forms 

 salts, which for the most part crystallize with difficulty or not at all. 

 A crystalline double salt, however, is readily formed with methyl- 

 iodide. The crystals of narcotine prepared on microscopic slides 

 from alcoholic solution vary in length from 0.4 mm. to 2 mm. 

 (Fig. 124). 



Papaverine occurs to the extent of about 1 per cent and forms 

 colorless needles or prisms, which are partly soluble in water and 

 alcohol, and colored deep purple or violet-blue on warming with 

 sulphuric acid. 



Thebaine (gramorphine) occurs to the extent of 0.15 per cent in 

 opium. It crystallizes in prisms which are insoluble in water or 

 alkaline solutions, soluble in alcohol, and gives with sulphuric acid a 

 deep red color. 



