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1286

ELEMENTS OF MATERIA MEDICA.

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It deserves especial notice that many substances enjoy equally with me ?°o 0 ,vin!f afepower of communicating'a red colour to the sesquisalts of iron. The J° sflbj®

some of them:—the acetates, hydrosulphocyanic acid, and the Sulph °c yan ll%. and.i» *'of man and of the sheep, infusion of white mustard, metamecomc, pyromecont > 6 il»e r 'gotic acids, the liquid obtained by the action of hydrochloric acid on detoiiat ^the decoctions of Cetraria islandica (p. 568) and Gigartina Helminthocorton (P- ff ithe 0 .

Meconic acid is an inert substance. Serliirner swallowed five grains 0 g) e ng> nlobserving any effect. Sdmmering gave ten grains to a dog; Feneglio an c asc s lll>eight grains to dogs, crows, and frogs, and four grains to various men : >*j ba seS ’

effects were observed (Richter, Ausf. Arzneim. Bd. ii. S. 616). Combined w*^ aS getit doubtless modifies their action. Meconate of soda, however, is not ac jjfjed by ll5tiirner asserted. It is supposed that the effect of the morphia on opium is m*,’ . , jo

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combination with meconic acid. I have already mentioned that this acid 'jj. S: j ]0 vve ver jan antidote in cases of poisoning by bichloride of mercury (see p. 479). 1 scarcitythe statement be true, the fact is of little practical value, on account of th ^ n ciiHAthe acid; for neither opium nor laudanum can be given in quantity stifficien ot [jer » 0< jilize the effect of this salt, without proving deleterious. Moreover, we have a cllJ

and easily accessible antidotes. Anthelmintic properties have been ascribedand some of its salts.

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Chemical Characteristics. —Litmus paper is reddened by ® {0 »

infusion of opium (or tincture of opium diluted with water),free acid ( meconic ). Sesquichloride of iron gives it a deep rc £ . 0 pioi 19(i meconate of iron). Acetate and diacetate of lead occasion agrey precipitate (i meconate and sulphate of lead, with colouringwhich, treated by sulphuric acid or sulphuretted hydrogen, y\ e -j e o>meconic acid, known by its reddening the persalts of iron, ^nbarium also causes a precipitate (meconate and sulphate of c n a)’Ammonia renders the infusion turbid ( precipitated morphia and naTincture of nutgalls causes a precipitate ( tannates of morphia an . ^ 0 f

Nitric acid communicates to the infusion a red colour (oscidt3 e jpjtat®phia ). Iodic acid and starch cause, after some hours, a blue J ( le 0

(iodide of starch). This last test does not always succeed. L 1

cal'*

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gold causes a deep fawn-coloured precipitate.

Application to Medico-legal purposes. —On examining the alimentary u p 0 jsoi>persons destroyed by opium, it not unfrequently happens that no traces ofcan be obtained. I have met with several instances of this, and others are aI id'^by Or. Christison (On Poisons). Either, therefore, opium is rapidly absorbe , ^ ounassimilated parts thrown out of the system by the excretories, or the consthis substance are digestible and assimilable. , A c al a11

The characters available for the detection of opium are two-fold,—P"”chemical. _ ] , ; n w at 5 e

1. Physical Characteristics.— Whether in the solid state °r dissolve,^or spirit, opium possesses three physical properties, by one or more of whic ^frequently recognized. These are, a more or less brown colour, a remarkable 11 1» ll ! e !*>rodour, and a bitter taste. Of these the odour is the only characteristic one. e ]iif)mentary canal it is strongest when the stomach is just opened, or when the oj) ^ Jis just reaching the boiling point. Other odours, however, frequently mas

analogy between the odours of lactucarium and opium deserves notice. for

2. Chemical Characteristics. —The ehemieal tests of opium are 1 '? on ju£»conic acid and morphia, above mentioned. In a case of suspected P°'j* e Jig 1 -’**^stomach and duodenum (cut into small pieces), with their contents, are to s ]ju,

in distilled water, and the solution filtered successively through a sieve,paper. A little acetic acid added to the water coagulates any caseum, an a cco ullt c )ito facilitate the solution of the morphia. Its presence is objectionable, on j >vli'the red colour produced by the action of the acetates on the ferruginous salts,simulates that developed with these salts by meconic acid. ., a ppb ^

(a.) Application of trial tests. —To a small portion of the filtered li<l ulfollowing tests:—

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