176 On the preparation of Opium for the China market. [March, 



we can, chemically, see, we obtain by our analysis the whole of the 

 morphia that is contained in opium. I suspect that the narcotic power 

 is partly lodged in some unknown substance (not narcotine) insoluble 

 in water : for I have, after careful and repeated washing, until it ceas- 

 ed to colour the water, found the insoluble residuum to act as an opi- 

 ate with considerable energy. Although morphia, in a state of 

 purity, can, like sulphur, be fused without change ; yet, when in com- 

 bination with the other constituents of opium, it is partly destroyed by 

 a much lower degree of heat, greatly under that of boiling water ; for 

 the pharmaceutical and Chinese extracts are found to contain very 

 little morphia : still, the former, as is well known, exert great medici- 

 nal power, out of all proportion to the quantity of morphia which 

 analysis evolves from them. From all these considerations it would 

 result, that the proportion of morphia obtained, by the analysis at 

 present known, cannot be regarded as a true exponent of the total 

 narcotic power of the opium which yields it. An additional source of 

 fallacy in comparing the produce of different countries exists in the 

 varying proportions which they contain of colouring matter or extrac- 

 tion ; a principle for which morphia and narcotine have a strong affi- 

 nity, forming insoluble compounds* with it ; and which, as well as 

 narcotine, is much more abundant in Indian than in Turkey opium. 

 Hence a considerable loss in the purification of morphia from the 

 former, and an apparent, and probably real, inferiority in its quantity ; 

 although we know that good India opium is equal to Turkey in narco- 

 tic power. 



25. Robiquet's process is the one employed by the opium exam- 

 iner in Calcutta. The chief precautions necessary to ensure success 

 and uniformity in its results are, not to use too much water at first ; 

 to see that the magnesia is brought to a red heat ; not to expose any 

 of the subjects of analysis to the sun, or to artificial heat, except in the 

 washing and final solution in alcohol of the morphia ; not to use too 

 strong a spirit in washing the morphia and excess magnesia ; and 

 to employ the strongest alcohol for its final solution before crystalliza- 

 tion. Sertuerner's process is useful where it is not necessary to 

 obtain the morphia in a separate state : and in practised hands affords 

 speedy and tolerably accurate information. It is probable that Robi- 

 quet's process will in time be superseded by that of the late Dr. 

 William Gregory of Edinburgh, which does not acquire the expen- 

 sive use of alcohol, and yields more morphia, by 30 or 40 per cent. ; 

 affording, in fact, the cheapest medicinal preparation known of Turkey 



* This may partly account for the medicinal activity of the mass of opium 

 above noticed- 



