rectified spirit, on equal quantities of the same coarse powder of foxglove; the former will, after equal digestion, be brown, and the latter a brilliant green: the taste of both will be exceedingly bitter. If the residue of both be filtered off, and an equal quantity of rectified spirit be digested on each, the residuum of that on which proof spirit had been previously digested will afford a brilliant green tincture, and the other a tincture of pale hue. Thus the green matter of the leaf is but little soluble in proof spirit, although largely soluble in rectified spirit. We do not know whether this is merely chromulite, or whether it is this substance, combined with the active principles, if there be more than one; and hence, in this state of uncertainty, it is prudent to retain the green matter. The resin, which is supposed by some to be the medicinal agent, the essential oil, the fixed oil, the fatty substance, and the bitter principle, are all soluble in rectified spirit; but we are not so certain that they are equally soluble in proof.

This point settled, the plan which I propose is easily executed it requires no skill, and can scarcely fail, if common care be taken. It consists in plucking the proper leaves off the living plant on the spot where it grows, instantly throwing them into the strongest alcohol, digesting for six weeks, pressing out the tincture, and filtering it. Here all the sources of deterioration are obviated, and we preserve the virtues of the recent plant unimpaired.

The ratio of the recent plant to the rectified spirit may be so contrived that the resulting tincture shall correspond with the ratio of the dried plant to the proof spirit as indicated in the Dublin Pharmacopoeia.

I found from a mean of four trials that 100 grains of digitalis leaves, of a moderate size, gathered in dry weather, and immediately dried in a well-regulated fire-heat, lost seventy-nine grains of water. The same experiments made on small leaves

proved a loss of eighty-three grains for every hundred. Thus the mean loss of leaves of a moderate and small size is eightyone grains on every hundred; and the numerical strength of the dried leaves is to that of the recent as five one-quarter to one. Hence ten ounces and a-half, Troy, of the recent leaves, would be equivalent to two ounces dried; and there would remain eight ounces and a-half by weight, that is 8.94 ounces, by measure, of water. If to this quantity of water contained in the recent plant we add 8.74 ounces of alcohol (0.814,) we shall have seventeen ounces and a half by measure of proof spirit, allowing for condensation, (instead of the sixteen ounces indicated in the pharmacopoeia for two ounces of dried foxglove,) which is one ounce and a half too much. But if ninety grains of pow. der of foxglove be added, the whole will be of the pharmacopœial strength, so far as ratio of the ingredients is concerned. But the quantity of liquid being inadequate to cover the leaves, the bottle containing the ingredients should be digested for a month, one day standing on its bottom and the next inverted on its top.

The resulting tincture will be of an olive-brown colour, because the red colouring matter, observed by Welding, will only be dissolved, and the chromulite will not. This must happen while we adhere to the ratio of the colleges. But we can obtain a brilliant green tincture by regulating the ratio so that the menstruum will be reduced to the strength of rectified spirit (0.840).

In order to do this, let ten ounces and a half, Troy, of leaves be pulled from the growing plant, and plunged into a bottle containing two pints and three-quarters (wine-gallon measure) of alcohol 0.815. The strength of the alcohol will be reduced by the water to the strength of rectified spirit (0.840), and after the proper digestion, a brilliant green tincture will result, as perfect as it is possible to procure it. The strength of this tincture, compared with that produced by the

process of the Dublin Pharmacopoeia, will be, so far as ratio is concerned, as one to three, and hence it might be given in three times the quantity for a dose. But as there is every reason to believe that its strength is incommensurate with this ratio, it might be prudent to begin with the same doses as have been always employed.

In this case the leaves will be covered by the alcohol; but a month's digestion in a warm place will be required, with frequent agitation,

The defects of the tincture of digitalis, made according to the British Pharmacopoeias, have been fully appreciated in other countries, and we find that efforts have been made to remedy them. The ethereal tincture of the Codex Français, (both 1816 and 1834,) as well as of some other continental pharmacopoeias, is, perhaps, intended to obviate the inefficiency of the British formulæ, but the solvent power of ether on the active ingredient is rendered very doubtful by the contradictory statements which have been made on this subject.

The Dresden Pharmacopoeia contains a formula, the object of which seems to be the attainment of the same advantages as are contemplated by mine. The recently expressed juice of foxglove is to be mixed with an equal weight of spirit of wine, and the mixture filtered. But the foregoing pages contain my reasons for believing it doubtful that the juice possesses all the qualities of the leaves, and that if it did, the feeble alcohol employed would not be competent to hold them dissolved. A formula for the preparation of tinctures of this kind has been given in the Bulletin des Travaux de la Société de Pharmacie for 1830.

In conclusion, I am compelled to believe, that our tincture of digitalis is far from being the best preparation of which the plant is susceptible: and I suggest to practitioners a trial of the process given in this communication. This trial should not be made by apothecaries in compounding prescriptions of physicians or surgeons: they are bound to the pharmacopoeial pro

cess, and it would be great impropriety in them to substitute any preparation of a more active nature than is there indicated, unless with the full knowledge and approbation of the prescriber.

11, CLARE-STREET, DUBLIN.

ART. VI. Observations on the Purulent Ophthalmia of Newborn Infants; on the Cause of the Disease; its Progress in the Eye; and Manner the Destruction of the Organ is sometimes effected by it; as also of its Treatment. By HUGH CARMICHAEL, A. M., Member of the Royal College of Surgeons in Ireland, one of the Surgeons of the Coombe Lying-in Hospital, and formerly of the Dublin Eye Infir

mary.

THE eyes of children, a short time after birth, are liable to become the subject of an ophthalmia, which, if it do not subside of itself or yield to the intervention of art, terminates in the destruction of vision, attended generally with considerable deformity.

A profuse discharge of purulent matter being the most prominent feature of the disease, it has thence, coupled with the period of life at which it occurs, obtained the name of purulent ophthalmia of new-born infants. The correctness of this term has, however, been questioned by writers, the principal source of the danger (the inflammation) being thereby overlooked while the attention is directed to a symptom comparatively of but little importance, (the discharge,) and whose presence is productive of inconvenience rather than any thing very injurious to the eye.

The disease, however induced, is, after its formation, to be regarded as of an inflammatory description. The cause of its occasional unfortunate termination is also the result of inflammation and its consequences on the cornea, which, as I shall endeavour in the sequel to shew, is not only liable to be more easily in

vaded by it at these periods of life, but when so is likewise less capable of resisting its effects. Hence, in the treatment, the means calculated to subdue or avert inflammation must be chiefly held in view, having, of course, regard to the delicate frame of the patient; when, however, destruction has happened to any part of the cornea, other circumstances must then be taken into account to be mentioned more fully hereafter.

The purulent ophthalmia of new born infants, if met with at or immediately after its commencement, such, for example, as it admits of being in midwifery practice, is in almost all instances capable of removal by very simple means, certainly in by far the majority of them; it would even appear sometimes to get well of itself without any interference whatever; occasionally, however it happens, that this favourable period for its treatment has gone by before it is seen, when another and more serious one sets in, and where, in defiance of our best efforts, the disease may run on to an unfavourable issue. Having had an opportunity of observing it in all its various stages during a period of several years that I was attached to an institution for the treatment of diseases of the eye formerly in this city, it often appeared to me, that in some respects, its nature, and the changes through which it passes to its final termination, were not perhaps fully understood, and the opinions I then formed respecting it being since confirmed in the opportunity I have had of late years of observing it under a more immediate inspection at the Coombe Lying-in Hospital, induces me to submit these opinions to the consideration of the Profession, particularly as I think, that should I be correct in them, the treatment of a disease so often destructive to vision, may thereby, perhaps, be to some extent improved.

Although I have said that the disease at its commencement generally admits of an easy and efficacious treatment, I cannot, however, agree with those who look upon it even then as of but minor importance in every instance, or that if it be seen before the cornea is invaded, it may always be conducted to a