196 DR, T. ANDERSON ON SOME OF THE 



Papaverine. 



In the purification of narcotine by repeated crystallizations from boiling alco- 

 hol, in the manner described in the paper already referred to, the mother liquors 

 of each successive crystallization had been carefully preserved, and at the conclu- 

 sion of the investigation they were worked up for the purpose of obtaining the 

 very considerable quantity of narcotine which they obviously still contained. For 

 this purpose the fluids were mixed together, and the greater part of the alcohol 

 separated by distillation. The residue on being left to itself, deposited a con- 

 siderable quantity of dark-coloured crystals mixed with resinous matters, which 

 were collected on a cloth and expressed, and the fluid which passed through was 

 again concentrated and allowed to crystallize, and this was repeated until it 

 ceased to yield anything on further evaporation. The crystals so obtained were 

 dissolved in the smallest possible quantity of boiling alcohol, from which they 

 were deposited in a tolerably colourless state as the liquid cooled. On further 

 concentrating this mother liquor, and again allowing it to cool, it became 

 filled with crystals of a substance obviously much more soluble in alcohol 

 than narcotine, and differing from it in its general characters. It was parti- 

 cularly observed to restore the blue of reddened litmus, to dissolve readily in 

 acids, and to saturate them completely ; properties not possessed by narcotine. 

 Its ready solubility in alcohol led at first to the suspicion that it might be the- 

 baine, which had been already observed accompanying the narcotine, but the 

 difference in its crystalline form, as well as its complete precipitation from its 

 solution in acetic acid, by subacetate of lead, proved it to be different. A very 

 few experiments sufficed to show that the base thus obtained was still conta- 

 minated with narcotine, from which it might no doubt have been separated by 

 repeated crystallizations ; but as this would have been an extremely tedious pro- 

 cess, and have caused the loss of a considerable quantity of material, I preferred 

 a method founded on the marked difference between its basic properties and those 

 of narcotine. The whole of the crystals obtained from the mother liquors, and con- 

 sisting partly of narcotine and partly of this other base, were reduced to a fine 

 powder, and digested with a limited quantity of acetic acid. The acid was ra- 

 pidly saturated, and as soon as the fluid had lost its acid reaction it was filtered 

 from the undissolved portion, which was again treated with the acid ; and this 

 treatment was cautiously repeated as long as it continued to be thoroughly satu- 

 rated. The solution was then filtered from the undissolved narcotine, precipitated 

 by ammonia, and the precipitate crystallized from boiling alcohol. The base was 

 now pure, and analysis showed it to be papaverine, with which its characters were 

 found to agree in all respects. A consideration of the properties of papaverine 

 now enabled me to perceive that it must have been present in very large quan- 

 tity in the mother liquor obtained in the first crystallization of the crude narco- 



