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ELEMENTS OF MATERIA MEDICA.

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4. Action of Opium on the different organs. —In discussing d 118 0 iject, it will be convenient to consider the organs arranged in g r0 *systems devoted to some common functions. dos eSj

a. On the Cerebrospinal System. —Taken in small or moderate ^opium first produces excitement of the vascular system of the

accompanied with corresponding excitement in the cerebro-spu

nal f‘ in !

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tions, as already stated. This state, however, is succeeded by 1 ^

depression. In large or poisonous doses the leading symptom is S °P athat is, a state analogous to profound sleep, from which the patieu . sbe roused, though with difficulty. In the latter stage of poisoningsymptom is succeeded by coma—that is, by profound sleep, fi° nl " jtJithe patient cannot be roused. Sopor is usually accompanied eith er ^, eractual paralysis of the muscular fibres, or with a diminished P° j l6almost amounting to it; both of which states doubtless arise fr° in gtsame condition of the cerebro-spinal system which produces sopcoma. This state is usually supposed to be sanguineous (venous; ^ di-gestion. The pupil is usually contracted,—a circumstance deser' moespecial notice. aI) d

But in some cases we have delirium in the place of sopor or colDa jj 0 nSconvulsions instead of paralysis. These are to be regarded as excep 1 ^to the general rule, and are accounted for, pathologically, by supp 0 sthey depend on a state of irritation or excitement set up in the « e I V incentres, and which usually, though not invariably, terminatecongestion. _ _ j, 0 l c

Another effect of opium is diminished sensibility. Thus the ' jbody becomes less susceptible of painful impressions ; in dangerous^.,fatal cases, the eyes are insensible to light,—the ears to sound- •state has been accounted for by supposing that the fimetions ot the s jfive nerves are diminished or suspended by the congested conditithe brain.

From these effects of opium on the cerehro-spinal system the following i»f eremay be drawn :—

(a.) That it is an objectionable agent in apoplexy, phrenitis, and paralysis. th e( b .) That under proper regulations it is a remedy which may he used to stim 11cerebro-vascular system, to promote sleep, to diminish inordinate muscular coutto diminish the sensibility of the body, and thereby to alleviate pain.

/3. On the Digestive System . —The usual effects of opium on the ». oJjof digestion are the following:—It diminishes secretion and exha ^

from the whole canal; thus it causes dryness of the mouth and t 1 s

and diminishes the liquidity of the stools: it excites thirst, j pyhunger, checks the digestive process (for in some animals poisontopium, food which they had taken a short time previously has beenin the stomach unchanged): and in some cases it excites vomiting- ^r (Med. Ohs. and Inq. vol. v. p. 321) tells us, that in the famine " ^railed in the East Indies, in the year 1770, opium was purchase 0 f

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prevailed m me n.ast maxes, in tne year 1771), opium t .the unhappy sufferers, at extraordinary prices, to allay the cravujn^hunger, and to banish the dreadful prospect of death. The j. ccouriers, who travel immense distances in a short period of tun 1 '’ p )Copium only during the journey, to support them. It diminish®sensibility and contractility of the digestive organs: hence the dim . olJin severe cases of poisoning, of producing vomiting. The constip jwhich follows the use of opium depends partly on the same cause;