extractive. It was deposited upon the sides of the vessel in the form of a brownish mass, in which, after some time, prismatic crystals of meconate of morphium were produced.

"15. The residue was digested with alcohol at an elevated temperature. The brownish liquor filtered deposited, after having been cooled to 5o C., the salt described by Derosne. This salt, by means of its morphium, restores the colour of reddened litmus paper, and has a weak action upon the ferrugineous salts by its meconic acid. At the same time there was deposited at the bottom of the vessel a coloured substance, which, when treated with alcohol, gave a little sub-meconate of morphium. The residue, which was very soluble in alcohol but almost insoluble in water, contained the combination of morphium with the extractive and the brown substance, which has been mentioned before (12). The combination of morphium with extractive is distinguished from resins by this property; also the extractive can be separated from it only with difficulty. Ammonia dissolves still less of it, and diminishes its solubility in water. The remainder, treated once more with alcohol, gave a coloured tincture, which was much thickened by adding water, and did not regain its transparency upon the addition of acetic acid; hence it follows, that the precipitate comes from an oil. The solution contained so little of the combination mentioned above, that the taste was scarcely bitter.

"16. It follows from these observations, that cold water dissolves the meconate of morphium with excess of acid, and almost all the extractive; and that the residue contains submeconate of morphium, which is rather insoluble in water, with a little extractive, which is easily dissolved by cold alcohol, but is almost all deposited in crystals.

"Conclusions.-17. Without noticing the accidental mixtures which have not been taken into account in this place, but of which I have spoken in my former researches, the crude opium of commerce is composed of meconate of morphium with little acid, which is divided by warm water into insoluble submeconate of morphium and into acid meconate of morphium, very soluble in water; supposing that there are no other vegetable acids intermixed, which may redden the litmus paper. The

extractive, like the morphium, is divided into two portions; of which, one, which is free, dissolves in cold water; the other part, undoubtedly never oxidized, remains in the residue with the sub-meconate of morphium, and forms by digestion with alcohol some sub-meconate of morphium, and a combination of morphium with extractive, almost insoluble in water, but very soluble in the acids.

"Water, when warm, dissolves more morphium than when cold; and morphium is precipitated in the cold from the liquor in combination with a little meconic acid and extractive. The resinous substance and the other constituent parts of opium, have no influence upon its medical virtues; because they are almost insoluble in water as well as in alcohol. Hence there is a great difference between the extract of opium which is prepared with warm water, and that which is prepared with cold; the latter being much more powerful than the former. The tinctures of opium ought to be prepared with pure alcohol, because by it only are the combinations mentioned above dissolved. These tinctures ought not to be kept in places where the temperance is too cold, because some of the salt of morphium will be precipitated. These inconveniences might be obviated by adding a little of the acetic acid, if we were sure that the acetate of morphium possessed the same medical properties as opium, or the meconate of morphium.

"The extract of indigenous poppy-heads prepared with distilled water, gave no signs of morphium when treated with ammonia, even when acetic acid was added. It appears, that this plant contains morphium combined with extractive. I could discover no traces of meconic acid in it. Other chemists who have examined opium, seem to have obtained different results.

"APPENDIX. I had proceeded thus far in my memoir, when I had occasion to make the following observations upon the preparation of morphium and meconic acid:

"1. Take eight ounces of opium in powder, rub it up with two or three ounces of concentrated acetic acid and a little distilled water; dilute the paste with two or three pounds of cold water, and filter the liquor. This slightly coloured solution conVOL. VIII. 2 Y No. 31.

tains acetate and meconate of morphium, extractive, and traces of the combination of extractive with morphium.

"2. Precipitate the morphium with ammonia, and evaporate the liquor to a fourth part; upon its cooling, separate the morphium by filtration, and precipitate the meconate of ammonia by a sufficient quantity of acetate of barytes. Upon evaporating the liquid to dryness, there is still deposited a little meconate of barytes. The extract from which the acetates had been separated by concentrated alcohol, is almost pure extractive. I have taken it in a dose of ten grains without the least inconvenience.

"3. The residue (1) contains the combination of extractive in excess with morphium, which is rather insoluble in water. I treated it at several times with sulphuric acid diluted with six parts of water; and I decomposed the acid solution by ammonia. This decomposition was not complete, for there always remains some morphium with an excess of extractive, of brown meconic acid, and a trace of sulphuric acid. This acid extractive, or brown meconic acid, is without effect: it is morphium which communicates to it its pernicious properties.

"Conclusions.-Crude opium then contains neutral extractive and acid extractive, which both exert no effect upon the ani. mal economy. The latter is combined with morphium; but it combines also with the meconate of morphium, and becomes soluble in water. This combination is decomposed only in part by the water; for the residue contains traces of meconic acid, which, forming a triple combination with a large quantity of morphium and extractive, dissolves in water only by degrees. This is the reason why the extract of opium prepared with cold water, contains only a part of the meconate of morphium, and a little of the combination of morphium with the extractive. By adding acetic acid, this combination loses a part of its morphium; and the meconate of morphium separates from the brown meconate of morphium."

A Practical Inquiry into the Causes of the frequent Failure of the Operations of Depression and of the Extraction of the Cataract, as usually performed; with the Description of a Series of new and improved Operations, by the Practice of which most of these Causes of Failure may be avoided. Illustrated by tables of the comparative Success of the new and old Modes of Practice. By Sir WILIAM ADAMS, Member of the Royal College of Surgeons in London, Oculist Extraordinary to his Royal Highness the Prince Regent, &c. London, 1817.

[From the Annals of Medicine and Surgery, December, 1817.]

PERHAPS no regular oculist acquired in the same short period such high popularity as Sir William Adams, and certainly in the midst of popularity never was any one before so bitterly assailed. Without the assistance of any private interest in either the fashionable or the commercial world, to which, not to merit, too many of our profession owe their elevation, Sir William Adams has worked his way, acquiring friends by his own exertions, from insignificance to the rank of the first oculist of London. But from his very outset he has had constant warfare. First accused of ingratitude by his master, he has been ever since attacked by some one or other in pamphlets, journals, letters, and conversation; called ignorant, ungrateful, illiberal, arrogant, and ten thousand other hard names, for which the great revenue of his practice does not appear to us, with our fine feelings, any thing like a compensation.

Seeing him thus extraordinarily distinguished in two very opposite respects, we may fairly draw two general conclusions, that he must have some degree of professional merit, and that he has some faults of character; that at any rate he must be an industrious man, and that at least he perhaps is over-eager and speaks his mind too freely. We have it however now in our power to decide more minutely-to ascertain whether he has the merit of improvement and originality, and whether his faults are of a darker stain.

The work upon cataract consists of four chapters, of which we purpose to give a full analysis.

I. History and Nature of Cataract.-After stating the errone us opinions of the ancients in regard to the seat of cataract, and the discovery of its real nature in the seventh century, after the celebrated astronomer Kepler had shown the transparency of the lens, the abandonment of this discovery, and the revival of the truth in the beginning of the eighth century; he proceeds to the history of the disease, and mentions an instance, under his own observation, of the complete ossification of the lens. A quotation is given from Pliny (lib. xxv. cap. 13.), which proves, that the ancients applied vegetable matters to the eyes for the purpose of dilating the pupils, previously to the operation of couching. "Pupillas dilatat, et ideo hoc inunguntur ante, quibus Paraceuthesis sit." We could almost wish this remark had come from some other person, rather than our author, who makes it, however, naturally enough, when urging the necessity of dilating the pupil to learn the existence of that species of cataract which depends on the opacity of the posterior part of the capsule of the lens,-a species too frequently mistaken for amaurosis, and entirely unnoticed by many eminent writers,-particularly mentioned in Sir W. Adams's for ner work, after the successful treatment of a remarkable case of that kind,—and subsequently spoken of by Mr. Travers.

The belief of Mr. Travers, that the lens is enclosed in a duplicature of the vitreous membrane, he shows to be in opposition to Richter, Janin, Scarpa, De Wenzel the younger, Ware, De Gravers, and Zinn; and contends, from facts which he himself has witnessed, that the lens has a capsule of its own.

"In operations for artificial pupil, performed on two ladies five years ago, the capsule of the crystalline in each was so hard and thick, that, although I had no difficulty in dividing the iris with the artificial pupil knife, yet it made no kind of impression on the capsule of the lens; which, with its contents, became spontaneously depressed below the margin of the pupil as soon as it was detached from the posterior part of the iris. To this time no alteration whatever has taken place ei