MM. Majendie and Robiquet have proved that it is the salt obtained by Derosne. The components of narcotina are, carbon 68.88, nitrogen 7.21, hydrogen 5.91, oxygen 18.00, in 100 parts1; or, according to Liebeg, of 65 of carbon + 5.5 of hydrogen +2.51 of nitrogen +26.99 of oxygen in 100 parts. Robiquet has proposed a mode of preparing an extract free from narcotina, and yet containing morphia. (See Extr actum Opii.)

1 To separate morphia from narcotina, Mr. Robertson (Edin. Journ. xxxvii.. p. 275) recommends to boil the salt with hydrochlorate of ammonia as long as any ammonia is driven off. The morphia is thus formed into the hydrochlorate, whilst the narcotina remains as a white insoluble powder.

In repeating Sertiirner and Robiquet's experiments, I obtained from good Turkey opium nearly three times the quantity of morphia yielded by the same weight of East Indian opium; that from the latter was also more coloured, and in smaller crystals. Although the utmost nicety of manipulation was not attended to in my experiments, yet as both specimens were treated exactly in the same manner, they are sufficient to show the comparative richness of these varieties of the drug in this salt; and the result is certainly in favour of the opinion, that the narcotic property of opium depends on this alkaline salt; and accounts for the fact which has been stated above, that much larger doses of the East Indian than of Turkey opium are required to produce its sedative effect on the system.2 Mr. Brande procured a larger quantity of morphia from a carefully prepared sample of English opium than from the same weight of Turkey opium.3 Practitioners and physiologists in this country have made decisive experiments with morphia, to determine its effects on the animal economy; and their results agree with those of MM. Orfila and Majendie.4 The experiments of the former being made upon dogs, they can be regarded as important only inasmuch as they confirm the opinion, that opium owes its soporific powers to this salt, and displays the comparative activity of the different combinations of the salt.

Of the saline compounds he found the acetate the most powerful; but a solution of morphia in olive oil acts with still greater intensity, and with more than double the effect of the aqueous extract of opium. The experiments of M. Majendie, being made on the human subject, are more interesting. He found that a quarter of a grain of acetate of morphia produces the most beneficial effects that can be expected from an anodyne;

1 Ann. de Chimie, t. xxiv. p. 186.

2 Samples of East India opium have nevertheless yielded nearly as much morphia as is usually found in Turkey opium.

3 Manual, p. 128. 4 Nouveau Journ, de Medecine, t. i. p. 1. 23.

allaying pain, and procuring sleep, without, in any degree, affecting the cerebral functions: and I have been able, from my own experience, to verify this fact. The sulphate acts in a similar manner, but with less energy. The hydrochlorate is as powerful as the acetate, and is more easily and abundantly procured.1 It is probable that narceia is the product of the process for obtaining it.

4. Codeia crystallizes along with hydrochlorate of morphia, in making that salt, in proportions according to the character of the opium. Dr. Christison procured one-twelfth of hydrochlorate of codeia from a specimen of East Indian; Dr. Gregory one-thirtieth from Turkey opium. Pure codeia is in flat, colourless, transparent prisms: water at 60° dissolves 1.26 per cent., at 110° 3.7, and at 212° 5.9: it dissolves in ether. The solution is alkaline; it combines with alkalies, forming crystallizable salts. Codeia is not reddened by nitric acid. It is a compound of 31 eq. carbon = 189.72 + 20 hydrogen + 1 nitrogens 14.15 + 5 oxygenz= 40 equiv. 263.87 : its crystals contain 2 equiv. of water.

5. Meconina2 is also a white, transparent salt, in acicular crystals, soluble in 200 parts of water at 60°, and 24 at 212° : it is also soluble in ether, alcohol, and the volatile oils. It fuses and sublimes without change, and is neither alkaline nor acid. It is separated by precipitating the aqueous infusion of opium with ammonia, washing the precipitate until it is nearly colourless, then evaporating all the watery solutions to a thickish consistence, and leaving the whole at rest for three weeks. The granular mass is next to be separated from the fluid, pressed and dried with a gentle heat; the result is Meconina. It may be purified by dissolving it in boiling alcohol to form crystals, redissolving these in water, and digesting with animal charcoal, filtering whilst hot, and lastly crystallizing by spontaneous evaporation.

6. Narceia3 is found in the aqueous solution of opium, after it has been freed from the morphia and narcotina by ammonia, and the meconate of ammonia which remains has been decomposed by baryta. On boiling the solution to expel the

1 I have found that the best mode of preparing the hydrochlorate is to precipitate an aqueous solution of opium, by means of a solution of chloride of barium; hydrochlorate of morphia remains in solution, whilst an insoluble meconate of baryta is thrown down. This is separated from the solution by decantation and the filter. On evaporation, the hydrochlorate crystallizes in radiated or starlike tussocks, which are readily separated from the narcotina and other components of the opium by pressure. By repeated solutions and crystallizations, the hydrochlorate is obtained nearly free from colour.

2 Discovered by M. Couerbe in 1832.

3 Discovered by Pelleticr in 1832. '

; ammonia, and evaporating, the crystals which gradually form are Narceia. When purified, they are white, acicular prisms, inodorous, slightly bitter, and pungent; soluble in 375 parts of water at 60°, and 230 parts at 212°; and in hot alcohol: but they are insoluble in ether. They neutralize acids imperfectly; the salts, when concentrated, become blue; and on adding successive portions of water, then violet, rose-red, and ultimately colourless.