der my care, with cataracts in both eyes, which according to the accounts of his relations had existed from his birth. After he was received into the hospital, the following cir- Distinguished. light & colours cumstances were ascertained respecting his vision. The pupils contracted considerably when a lighted candle was placed before him, and dilated as soon as it was withdrawn. He was capable of distinguishing colours with tolerable accuracy, particularly the more bright and vivid ones.

This One eye

years old.

On the 6th of October the left eye was couched. operation was preferred to extraction, from a belief, that the couched at 7 cataracts were not solid, and as the injury done to the capsule by the operation would be less, there was not the same chance of inflammation, the disposition for which had been so strong in the former case. As the eye was not irritable, and was likely to be but little disturbed by this operation, every thing was previously got ready for ascertaining his knowledge of objects, as soon as the operation was over, should the circumstances prove favourable. The operation Effects of the was attended with success, and gave very little pain. The operation. eye was allowed ten minutes to recover itself: a round piece of card of a yellow colour, one inch in diameter, was then placed about six inches from it. He said immediately, that it was yellow, and on being asked its shape said, "Let me touch it, and I will tell you." Being told that he must not touch it, after looking for some time, he said it was round. A square blue card, nearly the same size, being put before him, he said it was blue and round. A triangular piece he also called round. The different colours of the objects placed before him he instantly decided on with great correctness, but had no idea of their form. He moved his eye to different distances, and seemed to see best at 6 or 7 inches. His focal distance has been since ascertained to be 7 inches. He was asked whether the object seemed to touch his eye, he said " No;" but when desired to say at what distance it was, he could not tell. These experiments were made in the theatre of the hospital, in which the operation was performed, before the surgeons and all the students. He was highly delighted with the pleasure of seeing, and said it was 66 so pretty," even when no object was before him, only the light upon his eye. The eye was covered,

and

after the operation.

Sense of vision and he was put to bed, and told to keep himself quiet, but upon the house-surgeon going to him half an hour afterwards, his eye was found uncovered, and he was looking at his bed curtains, which were close drawn. The bandage was replaced, but so delighted was the boy with seeing, that he again immediately removed it. This circumstance dis ́tressed the house-surgeon, who had been directed to prevent him from looking at any thing till the next day, when the experiment was to be repeated. Finding that he could not enforce his instructions, he thought it most advisable to repeat the experiment about two hours after the operation. At first the boy called the different cards round; but upon being shown a square, and asked if he could find any corners to it, he was very desirous of touching it. This being refused, he examined it for some time, and said at last that he had found a corner, and then readily counted the four corners of the square; and afterwards when a triangle was shown him, he counted the corners in the same way; but in doing so his eye went along the edge from corner to corner, naming them as he went along.

Next day, when I saw him, he told me he had seen "the soldiers with their fifes and pretty things." The guards in the morning had marched past the hospital with their band; on hearing the music he had got out of bed, and gone to the window to look at them. Seeing the bright barrels of the musquets, he must in his mind have connected them with the sounds which he heard, and mistaken them for musical instruments. On examining the eye 24 hours after the operation, the pupil was found to be clear. A pair of scissors was shown him, and he said it was a knife. On being told he was wrong, he could not make them out; but the moment he touched them he said they were scissors, and seemed delighted with the discovery. On being shown a guinea at the distance of 15 inches from his eye, he said it was a seven shilling piece, but placing it about 5 inches from his eye, he knew it to be a guinea; and made the same mistake, as often as the experiment was repeated.

From this time he was constantly improving himself by looking at, and examining with his hands, every thing within his reach, but he frequently forgot what he had learnt.

On

On the 10th I saw him again, and I told him his eye was so Sense of vision after the operwell, that he might go about as he pleased without leaving ation. the room. He immediately went to the window, and called out, "What is that moving?" I asked him what he thought it was? He said, "A dog drawing a wheelbarrow. There is one, two, three dogs drawing another. How very pretty!" These proved to be carts and horses on the road, which he saw from a two pair of stairs window.

On the 19th, the different coloured pieces of card were separately placed before his eye, and so little had he gained in thirteen days, that he could not without counting their corners one by one tell their shape. This he did with great facility, running his eye quickly along the outline, so that it was evident he was still learning, just as a child learns to read. He had got so far as to know the angles, when they were placed before him, and to count the number belonging to any one object.

The reason of his making so slow a progress was, that these figures had never been subjected to examination by touch, and were unlike any thing he was accustomed to see,

He had got so much the habit of assisting his eyes with his hands, that nothing but holding them could keep them from the object.

On the 26th the experiments were again repeated on the couched eye, to ascertain the degree of improvement which had been made. It was now found that the boy, on looking at any one of the cards in a good light, could tell the form nearly as readily as the colour.

From these two cases the following conclusions may be drawn:

That, where the eye, before the cataract is removed, has General con only been capable of discerning light, without being able to clusions, distinguish colours, objects after its removal will seem to touch the eye, and there will be no knowledge of their outline; which confirms the observations made by Mr. Cheselden:

That where the eye has previously distinguished colours, there must also be an imperfect knowledge of distances, but not of outline, which however will afterwards be very soon acquired, as happened in Mr. Ware's cases.

This is

Cataracts in

traction.

proved by the history of the first boy in the present Paper, who before the operation had no knowledge of colours or distances, but after it, when his eye had only arrived at the same state, that the second boy's was in before the operation, he had learnt that the objects were at a distance, and of different colours: that when a child has acquired a new sense, nothing but great pain or absolute coercion will prevent him from making use of it.

In a practical view, these cases confirm every thing, that thildren gene- has been stated by Mr. Pott and Mr. Ware, in proof of catally soft, and Couching pretaracts in children being generally soft, and in favour of ferable to ex- couching, as being the operation best adapted for removing them. They also lead us to a conclusion of no small importance, which has not before been adverted to; that, when the cataract has assumed a fluid form, the capsule, which is naturally a thin transparent membrane, has to resist the pressure of this fluid, which like every other diseased accumulation is liable to increase, and distend it, and therefore the capsule is rendered thicker and more opaque in its substance, like the coats of encysted tumours in general.

better.

The earlier the As such a change is liable to take place, the earlier the operation is performed the operation is performed in all children, who have cataracts completely formed, the greater is their chance of having distinct vision after the operation. It is unnecessary to point out the advantages to be derived from its being done at a more early age, independent of those respecting the operation itself.

Several kinds of Peruvian bark in the shops.

The three chief.

The common:

VI.

Experiments on various Species of Cinchona: by Mr.
VAUQUELIN*.

SEVERAL different kinds of cinchona are met with in

the shops, but the chief and most in use are the following three. First that formerly called by the vague name of Peruvian bark, and which appears to be taken from the cinchona of ficinalis L. This is externally of a gray colour, and inter

Abridged from the Annales de Chinis, vol. LIX, p. 113, Aug. 1806.

nally

nally of a pale red; thin, and convoluted from the contraction of the inner surface; smooth and as it were resinous in its fracture, but sometimes slightly fibrous; and of an astringent and bitter taste. Its powder is fawn coloured, mingled with a tinge of gray.

The second, known by the name of red bark, and some- the rel: times erroneously called in France quinquina pitton, is of a much deeper colour; commonly very thick; little if at all convoluted; fibrous, and not at all resinous in its fracture; with an astringent and very slightly bitter taste.

The third, or yellow bark, which is of most recent date, the yellow. must not be confounded with the Angustura bark, as is sometimes done by the French druggists. This is of a pale yellow colour; of a more bitter but less astringent taste than either of the preceding; partly woody, partly resinous in its fracture; and a little convoluted, according as it is more or less thick.

thod of dis

It would be of important service to the physician, as well No ready meas to the merchant, if there were any sure aud simple me- tinguishing thods of distinguishing the good kinds of cinchona from their goodness, such as are bad or damaged: but hitherto we have nothing to guide us except their appearance, which may be fallacious, and our judgment from which must depend on our individual skill and practice. Mr. Seguin indeed has said, Seguin mis. that the aqueous infusion of the good kinds possesses exclusively the property of precipitating infusion of tan, and that of the bad of precipitating auimal gelatine; but this is an errour, for there are several species of true cinchona, that do not precipitate tannin, and yet cure fever*.

I have compared the physical and chemical properties of the infusions of every kind of cinchona to be found in the shops, to which I have added that of some other vegetable substances, apparently analogons with cinchona, and which are said to have cured fever. The infusions were prepared with the same quantity of water, the same quantity of bark, at an equal temperature, and for au equal time, so that no difference could arise from the mode of preparation.

Our readers will recollect, that Seguin fancied he had discovered the febrifuge principle in cinchona to be nothing more or less than gelatine. See Journal, Vol. VI, p. 186.

taken.

SPEC.