400 Royal Society : — 



and, as will be shown hereafter, by the manner in which cotarnine is 

 decomposed by dilute nitric acid. 



III. Decompositions of Opianic Acid. 



Opianic acid is readily decomposed when heated with strong 

 hydriodic acid ; no iodine is set free, but iodide of methyle is formed 

 in considerable quantity at the same time as anon-volatile substance, 

 very easily altered by heat and exposure to air, especially if in contact 

 with alkali, the precise nature of which we have not yet been able to 

 ascertain. 



"When opianic acid is heated with an excess of a very strong solu- 

 tion of potash, it splits up into meconine and hemipinic acid. These 

 substances were found by experiment to be formed in proportions 

 corresponding to the equation 



2C 10 H lfQ 5 = C 10 H !0 Ol + C 10 H ,0 O 8 . 



Opianic acid. Meconine. Hemipinic acid. 



The meconine thus produced has all the characters which have been 

 ascribed by previous observers to meconine obtained by other processes ; 

 its identity was further established by analysis, and by the preparation 

 of chloro- and nitro-meconine, the former of which was analysed. 

 The hemipinic acid was also found to be identical with that obtained 

 irectly from narcotine : the acid and its silver-salt were analysed. 



Having thus found a method by which meconine and hemipinic 

 acid can be produced with certainty and in large quantities, we intend 

 to make an extended investigation of them and of opianic acid, in the 

 hope of discovering the nature of the relationship of these three bodies 

 to each other and to narcotine. The principal results which we have 

 hitherto obtained in this direction are as follows. 



Action of Hydriodic Acid on Meconine. — Meconine is decomposed 

 by hydriodic acid like opianic acid, giving iodide of methyle and an 

 easily alterable substance, the nature of which has not been deter- 

 mined. 



Action of Hydriodic Acid on Hemipinic Acid. — Hemipinic acid, 

 heated with concentrated hydriodic acid to within a few degrees of the 

 boiling-point of the latter substance, is decomposed into iodide of 

 methyle, carbonic acid, and an acid of the formula C 7 H G O 1 . It was 

 found by direct experiment that two atoms of iodide of methyle arc 

 formed from each atom of hemipinic acid, so that the following 

 equation probably represents the reaction : — 



C" H 10 0° + 2 HI = 2 CH 3 1 + CO 2 + C 7 H ' 

 Hemipinic acid. New acid. 



The new acid is moderately soluble in cold water, and very soluble 

 in boiling water, alcohol, and ether ; its solution has a strongly acid 

 reaction with test-paper. It separates from hot water in small needle- 

 shaped crystals containing 14 "80 per cent, water of crystallization, 

 which they lose at 100° (the formula C 7 IP 4 + 1 hW O corresponds 

 to 14-92 per cent, water) ; at a higher temperature the acid melts 

 and sublimes without apparent alteration. 



Dried at 100°, it gave the following results on analysis : — 



