Action of Chlorocyanic Acid
The Medical Gazette and the Lancet gave insertion to the following statement of mine, of date Oct. 20, 1842.
Sir,—In October, 1841, I gave an account of the action of the vapour of hydrocyanic acid upon diseases of the eye. Since that period I have been engaged in investigating the action of various other bodies on the same organ, and under the same form.
One reason why I did not rest satisfied with the effects produced by the hydrocyanic acid, was, that its action, like that of all other medicines, decreased in power by continued application; thereby rendering it necessary to have occasional recourse to other medicines, in order to insure a more speedy recovery. Another reason was, the reluctance of many individuals to submit the eye to the action of so potent a medicine.
The first medicines to which I shall refer, and which I have employed with some success, are the chlorocyanic acid and sulphuretted chyazic acid. The plan I pursue is that of putting a drachm of one of the medicines into a bottle (containing a small piece of sponge) of about two-ounce size, having a mouth precisely fitted to the eye, and with a ground-glass stopper.
The action of these medicines is very different from that of the hydrocyanic acid, in as far as they both stimulate the eye, and produce much greater warmth and irritation, with less dilatation of the pupil. Few, however, can bear the chlorocyanic acid to be applied longer to the eye than half a minute; though, in a minute after its application, all irritation is removed, and the eye feels perfectly at ease.
The next medicine which I have employed in the form of vapour was the chloruret of iodine. This medicine produces very little warmth or uneasiness to the eye, if continued for the space of two minutes or upwards; but a sensation of irritation, accompanied with a flow of tears, takes place on its removal. It contracts the pupil, and in no case have I seen it dilate it. Its vapour rises very readily, and does not leave the yellow disagreeable colouring on the skin produced by the vapour of iodine when uncombined, which is a great drawback in the use of iodine in diseases of the eye.
The last medicine which I have employed is the bisulphuret of carbon, which is so volatile, that the application of it to the eye, when the bottle is held in a warm hand for a few seconds, is as much as can be borne, in consequence of the intense prickling heat and flow of tears which it occasions. Owing to this fact, I generally use it by causing the patient to shut the eyelid during its application, which can then be continued for a minute or two, with the same beneficial effect upon the eye, without inconvenience to the patient. It generally contracts the pupil, and very seldom dilates it.
I used to employ iodine by putting it into the same bottles, and immersing it in hot water, and in its state of vapour applying it to the eye; but I find it answers much better when dissolved in the bisulphuret of carbon.
It is my intention, shortly, to give a full account of the action of these medicines upon the various forms of disease to which the eye is subject, and also what particular disease each medicine is best calculated to remove. At the same time I shall state such instances of failure as have occurred in my experience, in order that a just estimate may be formed of the value and importance of each medicine.