A dictionary of practical surgery: comprehending all the most interesting improvements, from the earliest times down to the present period : an account of the instruments, remedies and applications employed in surgery : the etymology and signification of the principal terms : ... forming together a "catalogue raisonné" of surgical literature (Volume 2).

  • Cooper, Samuel, 1780-1848.
Date:
1823
Catalogue details

Licence: Public Domain Mark

Credit: A dictionary of practical surgery: comprehending all the most interesting improvements, from the earliest times down to the present period : an account of the instruments, remedies and applications employed in surgery : the etymology and signification of the principal terms : ... forming together a "catalogue raisonné" of surgical literature (Volume 2). Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    sw sOL 419 be thing looked at. Tl tumc- oua the objects are between the eye arid the principal tiling looked at, the more dis- tant it is made to appear; the fewer i the nearer it seems to be. In a coun- try covered with snow, and upon the sea, distant objects appear to be close. The smaller an object is to the eye, in rcla- 1011 to ils known magnitude, the further off it seems. The errors which the eye makes in regard to the distance of objects, also lend to deceive. But, there are certain ea- rn which the eye is almost entirely inca- pable of judging of the distance of objects. The first is, when the object, of which we •wish to ascertain the distance, is looked at with only one eye. Hence all one-eyed persons, and persons affected with strabis- mus, are unable to judge well of the real nee of objects. However, they are only so for a certain time ; and. by practice hey gradually acquire Ihe faculty. Even when two eyes are employed, it requires some exercise, in order to enable them to e of the right distance of objects. Per- i born blind, but who have their sight restored in both eyes by the operation for the cataract, are a long while incapable of nig of distances, and only obtain this er very gradually. Lastly, this infirmity •metimes owing to an irritation affecting the optic nerves, whereby their sensibility is so altered, that distant objects make the impression upon them of near ones. In this circumstance, all objects appear to the pa- tient closer than they really are. This is the only case, which admits of being treated as a disease. The irritation, producing the disorder, is mostly seated in the abdominal viscera, and requires evacuations and such medicines as invigorate the nerves. A sup- pression of the perspiration is alleged to be .-ometimes a cause (Richter, Avfangsgr. dcr Wundarzn. B. 3, p. 525.) A sound eye likewise does not always judge with accuracy and uniformity of the magnitude of objects. This may arise from Three causes. In order to judge rightly of size of any thing, its precise distance must be known : for the more remote it is, the smaller will it seem to the eye. Hence, any conjecture respecting the magnitude of an object is constantly erroneous, unless the distance be ascertained. Size is invari- ably something relative. A single large ob- ject, surrounded by many small ones, always appears to be larger than it really is, et vice versa. \n object whose magnitude is known, seems smaller than it actually is, when one has been a little previously looking at ano- ther that is still larger. Lastly, the refrac- ion of the rays of light in the eye, by which operation an object is made to appear large or small, is not always accomplished in the ame degree, as the eye is hot at all times equally full and distended with its humours. Hence, at one time, the same object will appear to the same eye, and at the same distance larger; at another time smaller. Sometimes, however, the eye judges so er- roneously of the magnitude of objects, that ii-regarding the case as an infirmity, or disease. It is for the most part. owing to J defective sensibility in the nerves, caused by some species of irritation acting upon the eye, and generally seated in the gastric organs. A man, to whom every thing seemed one half smaller and nearer than it really was, was cured by means of an emetic, bark, an issue and valerian. (Leutin, obs.fascic.) Sometimes to the eye, under circum- stances of disease, straight lines appear ser- pentine ; perpendicular objects, sloping, things standing upright, to be inverted, &lc All these cases are set down by Richter as depending upon a wrong sensibility of the nerves, occasioned by the effect of some irritation. The irritation, he says, may be of many kinds ; but experience proves that it is mostly seated in the gastric organs. These defects of -i.,ht may generally be cured by first exhibiting emetics and purga- tives, and afterward having recourse to re- medies for strengthening the nerves, bark, oleum animate, valerian, issues, &c. One mark of a very weak and irritable eye, is when objects, after being looked at a good while, and presenting a right appearance. begin to move, swim about, mix together, and, at length, become quite iudistiuguish able. This principally happens when the objects regarded are small and strongly illuminated. Here such remedies, both general and topical, as have the effect of invigorating the nerves, are indicated. How- ever, sometimes, the infirmity is partly ow- ing to the operation of some species of irri- tation, which will require removal, ere the tonic medicines and applications can avail. Indeed, in particular cases, the dispersion of such irritation is alone sufficient to ac- complish the cure. Sometimes, all objects appear to the eye, as if they were in a more or less dense mist. This defect in vision is always owing either to some slight opacity of one of the humours of the eye, or to excessive debility of the optic nerves. (See Richter, Anfangsgr. der Wundarzn. D. 3, p. 521, fyc.) SINUS.—A long, narrow, hollow track, leading from some abscess, diseased bone, SOLUTIO ARGENTI NITRATl.—R. Ar- genti nitrati 3j. Aq. distillat. zSs M. This is a very good application for sores, which are frequently met with round the roots of the nails, both of the fingers and toes. It is also useful in herpetic affections, noli-me- tangere, and several kinds of ulcers. The proportion of the argentum nitratum may be lessened, or increased, as occasion re- quires. A strong solution of this substance is a good application for destroying warts, to which it must be applied, by means of a hair-pencil. When used for sores, it is best to dip little bits of soft lint in it, lay them on the part affected, and cover them with a common pledget. SOLUTIO FERltl SULPHATIS.—R. Ferri sulphatis ad albidinem calcinati Aq. Distillat. ^viij. Misce. Has beei