1836.] On the preparation of Opium for the China market. 175 



the strata of the leaves, such as ' are sometimes found, lined with 

 mould, in faulty cakes, and the shell altogether ought to be thin, com- 

 pact, and of equal thickness throughout. The shape ought to be as 

 nearly spherical as possible : that being the geometrical form which 

 under the smallest surface contains the greatest quantity of matter, 

 and which consequently affords the least scope for the extrication of 

 air and ultimate injury to the shape of the cake when that air escapes. 

 Greater attention to having the earthen cups, in which the cakes are 

 dried, perfectly hemispherical, instead of parabolical as they now are, 

 would contribute to the desired sphericity. 



22. In opening a cake, the next thing to be attended to is the 

 manner in which the two hemispheres of the opium separate : the 

 Behar will be found to retain its shortness, while the Benares draws 

 out into threads. The smell should then be attentively observed and 

 noted down, being strongest immediately after the opening, and giving 

 at that instant the fairest indications of the state of the opium with 

 respect to preservation ; the pure narcotic, venous, or acescent odour 

 being then most strongly perceptible : in this respect the Benares will- 

 generally prove superior to the Behar. It is an important character ; 

 for the Chinese are great epicures in the flavour of opium, and object 

 to it when it smells at all sour. 



23. The surface of the opium should then be narrowly inspected, 

 and the tint and shade of colour, both by reflected and transmitted 

 light, noted down, in terms of Werner's nomenclature ; also the ap- 

 parent quantity of pase'wd if any be present, which is almost constantly 

 the case with Behar opium, where it appears like dark glistening fluid,, 

 lining the little cells in the surface of the opium. As the depth of the 

 colour of opium in the caked state depends on the quantity of pasewti 

 in it, or the degree in which it has been deteriorated by exposure to* 

 the sun, the lighter the shade, the better is the opium. 



24. The chemical analysis of opium, after all the trouble that has 

 been bestowed on it, is still in an unsatisfactory state. A perfect ana- 

 lysis, such as we possess of Peruvian bark, and of some other medicinal 

 plants yielding vegetable alkalies, ought to eliminate the whole of the 

 active principles, leaving nothing at its close but an inert mass pos- 

 sessed of no therapeutic power : and the essential principles thus ob- 

 tained should equal (or, as in the case of quina freed from its bulky 

 fibrous accompaniment, surpass) in activity, a quantity of the original 

 substance equal to that from which it was extracted. But how greatly 

 inferior are the powers, over the animal economy, of a grain of mor- 

 phia, in whatever state of purity or saline combination, to the quantity 

 of opium that is required to furnish that single grain ! Yet, for all that 



