This is thought to exist in belladonna, combined with malic acid in excess. For an account of the different somewhat complex processes by which it is extracted, the reader is referred to the U. S. Dispensatory. Mr. W. T. Luxton, of London, proposes the following simple method. To a decoction of the leaves he adds a little concentrated sulphuric acid, which precipitates the albumen and forms sulphate of atropia; then, having drawn off the clear liquor, he precipitates the atropia either by solution of ammonia, or the sesquicarbonate of that alkali. After a day or two the clear liquid is drawn off, and the crystals which have formed, having been thrown on a filter to dry, are washed with a little spirit of ammonia, which deprives them of most of their colouring matter, leaving them "moderately" white. He has thus generally obtained about 5.5 parts from 1000 of the leaves, while the process usually employed yields only 3 parts for 1000. (See Am. Journ. of Pharm., xxvii. 156).

Atropia is in white, translucent, silky, acicular crystals, inodorous, of a bitter acrid taste, slightly soluble in cold water, considerably more so in ether, very soluble in alcohol, and dissolved by all these liquids in larger proportion when hot than cold. It melts with heat, and at a higher temperature is dissipated; part being volatilized without change, and the remainder decomposed. It has an alkaline reaction with litmus-paper, and neutralizes the acids, forming crystallizable salts with the sulphuric, muriatic, and acetic. Nitric acid dissolves it, forming a yellow solution; sulphuric acid dissolves it without change of colour if cold, but when hot reddens it. Like the other organic bases, it is precipitated by the alkalies from its saline solutions, unless very feeble; and from the same solutions tannic acid throws down the tannate of atropia. Like most of these, too, it consists of carbon, hydrogen, oxygen, and nitrogen.

The effects produced upon the system by atropia are exactly those of belladonna, only that they occur more promptly, and are relatively much more powerful. Thus, the alkaloid gives evidence of its operation in twenty minutes, while the powdered leaves or extract usually require half an hour. Its action continues from twelve to twenty-four hours or longer. One-sixth of a grain, taken into the stomach, generally produces symptoms of a somewhat violent character, as accelerated pulse, dryness and stricture of the throat, dimness of vision with dilated pupil, giddiness, abnormal sounds, phantasms, delirium, and sometimes numbness and tingling of the extremities, and strangury, with depression of the circulation and temperature of the surface. Two-thirds of a grain have occasioned the most alarming symptoms, from which, however, recovery took place.

For internal use it has little advantage over the other preparations, while, from its small bulk, it might be more liable to be taken in poisonous quantities. Nevertheless, if pure, it may be more certainly depended on in a given dose, and danger may be avoided with care. It is applicable to the same diseases precisely as belladonna itself. The dose at first should never exceed the twelfth of a grain; and it would be best to commence with the twenty-fourth or thirtieth, which may be repeated two or three times daily, and increased if requisite.

Externally, especially for application to the eye, it is preferred by some to the extract, in consequence of the less quantity required, and its greater cleanliness. It may also be used with great effect endermically. It is chiefly employed to dilate the pupil, which it does very promptly, in exceedingly minute quantity. One drop of a solution, containing only a grain in a fluidounce of the menstruum, will produce the effect. M. Steafield recommends for this purpose the use of atropia paper, which may be made by saturating paper with the solution just mentioned, in such a way, that a little piece, about one-fifth of an inch square, shall be wet with exactly one drop of the solution. The paper is then dried, and, when wanted, may be applied by drawing down the lower lid, and placing the piece of paper upon the ball beneath the cornea. (Ann. de Therap., 1864, p. 33).

Atropia has also been used hypodermically for the relief of neuralgic affections. Its use in this way has greatly extended of late; and it has been employed in most other complaints in which belladonna has been thought to be useful. It seems to have been peculiarly efficacious in severe rheumatic pains of a subacute character, but of considerable duration, especially sciatica. One-twenty-fourth or one-sixteenth of a grain, dissolved in from fifteen to thirty minims of water, may be injected into the subcutaneous areolar tissue at one operation; but some cases of unexpected violence from its use in this way have led to peculiar caution in regard to the hypodermic dose; and it is now recommended not to administer by injection, at the first operation, more than one-half the quantity administered by the mouth. It is not improbable that, in the cases where alarming effects have been suddenly produced, the solution may have been injected directly into a punctured vein. To avoid such a result, the point of the instrument may be very slightly drawn back before the liquid is injected. A case is on record in which the 1/190 of a grain produced apparently serious effects.

The British Pharmacopoeia directs a Solution of Atropia (Liquor Atropine, Br.), made by dissolving four grains of the alkaloid in a fluid-ounce of a menstruum consisting of seven fluidrachms of distilled water and one of rectified spirit. Four minims, equivalent to one-thirtieth of a grain of atropia, may be given as a commencing dose, and increased if necessary to ten or twelve minims. Half the quantity may be used for subcutaneous injection. Diluted with four measures of distilled water, it may be used for dilating the pupil.

An Ointment of Atropia (UnGuentum Atropine, Br.) is also officinal in the British Pharmacopoeia, made by first dissolving eight grains of atropia in half a fluidrachm of rectified spirit, and afterwards mixing the solution with one ounce (avoirdupois) of prepared lard. In the application of this ointment, care must be taken that it do not come in contact with wounded, abraded, or ulcerated surfaces.

The U. S. Pharmacopoeia directs the Sulphate of Atropia (AtropiAe Sulphas, U. S.); but it has little advantage over the pure alkaloid, which may be dissolved in water with the utmost facility by means of a little acetic acid. Valerianate of atropia has also been recommended as peculiarly efficacious in asthma; but the dose of valerianic acid is so controlled by that of atropia that it can scarcely exercise any observable influence. The following preparations may be made for use. Dissolve one grain of atropia in a fluidrachm of alcohol, and add seven fluidrachms of distilled water to the solution; or mix a grain with a fluidounce of pure water, and drop in diluted acetic acid till the solution is effected. Of either of these preparations, fifteen minims may be given for a commencing dose, and a drop or two may be introduced into the eye in order to dilate the pupil. An ointment may be made by rubbing up five grains thoroughly with three drachms of lard; of which a portion about as large as a pea may be used in friction to the eyelids and face, to dilate the pupil, or relieve neuralgia. Another method is to paint the eyelid with a solution of atropia in a chloroformic solution of gutta percha. When atropia is applied to a blistered surface, or that of an ulcer,, not more than the dose given by the mouth should be used at first, in consequence of its very rapid absorption. It causes when thus employed a slight pain, which soon ceases. A case of fatal poisoning is said to have occurred from the application to a blister on the neck of an ointment composed of 15.5 parts of sulphate of atropia and 700 parts of lard. (Pharm. Journ. and Trans., June, 1865, p. 664.)*

* Atropia and Morphia. Some interesting results have been recently obtained in regard to the physiological action of atropia, and of its relation with the alkaloid of opium. A series of observations on these points were undertaken, under favourable circumstances, jointly by Drs. S. Weir Mitchell, Wm. W. Keen, and Geo. R. Morehouse, of Philadelphia, which eventuated in the following conclusions; and these correspond very closely with the results of similar inquiries made about the same time by Dr. Da Costa, of this city, and subsequently by Dr. Erlenmeyer, of Bendorf, in Germany. In the experiments of Dr. Mitchell and his coadjutors, the alkaloids in solution were injected into the subcutaneous areolar tissue; the morphia, in the form of sulphate, in doses varying from one-third to one-fourth of a grain; the atropia, from one-fifteenth to one-thirtieth.

1. Circulation and Respiration

On the circulation, the first effect of atropia was for a few minutes either nothing, or a slight diminution in the frequency of the pulse; but uniformly this short period of quiescence or diminution (from 4 to 10 minutes) was followed by excitement; the pulse rising from 15 to 40 beats in a minute, continuing thus about an hour, then gradually subsiding till, after about 4 hours, it fell considerably below the natural standard. The greatest depression was in the tenth or eleventh hour, after which it rose again, and became normal in 24 hours. The respiration did not increase in frequency with the pulse, but either remained unaltered, or was slightly depressed.

After the injection of morphia, the pulse was not strikingly affected. In a few cases it rose slightly, in a larger number it was unchanged, and in a still larger number fell an average of 8 beats only; but the fulness was increased with the general influence of the morphia. The respiration was little affected. The general conclusion was that morphia subcutaneously administered, in ordinary remedial doses, has no conspicuous influence on the heart and lungs.

When the two alkaloids were administered conjointly, the result was precisely the same on the pulse and respiration as when the atropia was given alone; that is, its action was in no degree modified by the morphia.

The inference is that, in relation to the functions of circulation and respiration, there is no antagonism between atropia and morphia.

2. Action on the Eye

In their action on the eye, the alkaloids appeared, to a certain extent at least, to neutralize each other. When the pupil was dilated with atropia, the injection of morphia caused it, within half an hour, either to return to the normal standard, or to contract still further. So also with the power of accommodation, which, however, oftener remained paralyzed for an hour or more after the pupils began to show the influence of morphia; so that in this respect the opiate what acrid taste. They are stronger in medicinal qualities than any other part of the plant.