Cryptopine—exists in opium in very small proportion. T. and H. Smith state that since the alkaloid first came under their notice, they have collected of it altogether about 5 ounces in the form of hydrochlorate, and this small quantity in operating on many thousands of pounds of opium. But they by no means assert that the whole of the cryptopine was obtained.
Rhœadine—is also found only in exceedingly minute quantity.
Meconic Acid—If the average amount of morphine in opium be estimated at 15 per cent., and the alkaloid be supposed to exist as a tribasic meconate, it would require for saturation 3·4 per cent. of meconic acid. Wittstein obtained rather more than 3 per cent., T. and H. Smith 4 per cent., and Decharmes 4·33. Opium produced in Vermont yielded, according to Proctor (1870) 5·25 per cent. of meconic acid. The quantity of acid required to unite with the other bases assuming them to exist as salts can be but extremely small.
Estimation of Morphine in Opium—The practical valuation of opium turns in the first instance upon the estimation of the water present in the drug, and in the second upon the proportion which the latter contains of morphine.[277]
The first question is determined by exposing a known quantity of the drug divided into small slices or fragments to the heat of a water-bath until it cease to lose weight.
For the estimation of the morphine many processes have been devised, but none is perfectly satisfactory.[278] That which we recommend is thus performed:—Take of opium previously dried at 100° C., as above stated, and powdered, 10 grammes; shake it with 100 grammes alcohol 0·950 sp. gr., and filter after a day or two. The weight of the liquid should be made equal to 100 grammes. Add to it 50 grammes of ether and 2 grammes of ammonia water 0·960 sp. gr.; collect the crystals of opium which separate slowly, after a day or two, dry them at 100° C., and weigh them.—On applying this method to Indian opium, we were but little satisfied with it.
Commerce—By official statistics it appears that the quantity of opium imported into the United Kingdom in 1872 was 356,211 lb., valued at £361,503. The imports from Asiatic and European Turkey are stated in the same tables thus:—
| 1868 | 1870 | 1872 | 1874 |
| 317,133 lb. | 276,691 lb. | 325,572 lb. | 514,000 lb. |
It is thus evident that the drug used in Great Britain is chiefly Turkish. The import of opium from Persia has been very irregular. In 1871, 21,894 lb. are reported as received from that country; in 1872, none.
Except that a little Malwa opium has occasionally been imported, it may be asserted the opium of India is entirely unknown in the English market, and that none of it is to be found even in London in the warehouse of any druggist.