CRYSTALLINE CONSTITUENTS OF OPIUM. 209 



This leads to the formula C 20 H 9 (NOJ 8 , which is exactly the same as that 

 of the substance described by Couerbe under the name of hyponitromeconic acid. 

 This substance, according to Couerbe, is an acid capable of combining with the 

 alkalies, and yielding precipitates with the salts of iron and copper. It occurs in 

 long yellow needles, gives yellow solutions with water and alcohol, but not with 

 ether, and dissolves in the alkalies with a dark yellow, almost red colour, and is 

 precipitated by acids. It is said to melt at 302°. These characters, though dif- 

 fering very remarkably from those of nitropianyl, approximate so closely in other 

 respects that there can be no doubt about the identity of the two substances, al- 

 though the discrepancies are somewhat puzzling. Some of them may, no doubt, 

 be explained on the supposition that Couerbe"s substance was impure ; but others 

 scarcely admit of any such explanation. This particularly applies to his descrip- 

 tion of the mode in which it was obtained. He says that nitric acid is to be boiled 

 with meconine, and the fluid evaporated to complete expulsion of the acid, and the 

 residue, on treatment with water, gives hyponitromeconic acid. I found, on the 

 contrary, that the residue, which represented only a small quantity of the opianyl 

 or meconine employed, was highly soluble in water, and the solution gave, on 

 evaporation, an amorphous mass which dissolved in almost all proportions in alco- 

 hol and ether. In one instance only in which this process was tried, a small 

 quantity of a crystalline matter was obtained. The soluble substance was not 

 examined, as its properties were not such as to admit of easy purification. It is 

 probably a further substitution product. 



Action of Chlorine on Opianyl. 



When a current of chlorine is passed into a cold saturated solution of opianyl 

 in water, crystals soon begin to make their appearance, and gradually fill the 

 whole fluid. In preparing this substance in large quantity, it is convenient to 

 employ a warm solution, so that the bulk of the fluid may be smaller ; but in this 

 case care must be taken to stop the process before it has gone too far, as the 

 crystals are apt to diminish, or even disappear, apparently owing to the forma- 

 tion of a farther product of decomposition, and the same precaution is necessary, 

 though to a less degree, with the cold solution. The crystals are purified by solu- 

 tion in boiling alcohol. Chloropianyl may also be obtained by passing dry chlo- 

 rine over fused opianyl. The gas is rapidly absorbed, hydrochloric acid is evolved, 

 and the mass becomes gradually less and less fusible, so that the temperature of 

 the oil-bath in which the tube is immersed must be slightly raised. After the 

 action has gone on for some time, the current of gas must be stopped and the heat 

 removed. If the action has been properly managed, the mass is highly crystal- 

 line, and on solution in boiling alcohol gives crystals identical with those ob- 

 tained in the wet way. In this case, also, care must be taken to stop the ac- 

 tion at the proper point, for if it be continued too long, no crystals are obtained* 

 and the fluid solidifies into a resinous mass like Canada balsam. 



