This name has been given to a solution of gun cotton in ether, which was brought to the notice of the profession, in the year 1841, by Dr. J. P. Maynard, then a student of medicine in Boston. For the mode of preparing it, see the U. S. Dispensatory (12th ed.).

Properties

Collodion is a colourless, transparent liquid, of the consistence of thin syrup. On exposure to the air, the ether rapidly evaporates, and the solution thickens so as to be unfit for use. Hence, it must be kept in well-stopped bottles, and in very small ones, in order to obviate the necessity of frequently opening them. When the solution is spread out uniformly, by means of a brush, there is soon formed, in consequence of the evaporation of the ether, a thin, transparent, very tenacious pellicle, which adheres firmly to the surface with which it is in contact. This is impermeable by air, and insoluble in water, so as to protect the surface completely against those agents. But, in the process of solidification, the preparation undergoes considerable contraction, and acquires a certain degree of inelastic rigidity, which causes it, when applied to a yielding substance like the skin, to produce contraction. This last property, though useful for certain purposes in surgery, is very inconvenient for others; and for the latter should be corrected if possible.

Several different additions have been proposed, with various degrees of success, to obviate this inconvenience. An account of them may be seen in the article by Dr. Bache in the U. S. Dispensatory, before referred to. Among them glycerin, proposed by MM. Cap and Garot, is probably the most efficient. Two parts of glycerin added to 100 of collodion, according to these writers, entirely obviate the disadvantages alluded to, giving to the pellicle formed a pliability and elasticity which prevent injurious contraction, and permit free movement of the parts that may be covered.

Uses. in consequence of the adhesiveness and firmness of the pellicle formed by collodion, and of its impermeability by water and air, it answers an excellent purpose for retaining the surfaces of incised wounds in contact, as a dressing for ulcers in which contraction and the exclusion of atmospheric air are indicated, and as a covering for superficial abrasions, slight injuries, excoriated nipples, intertrigo, etc. inflammation is obviated, and the parts in general heal kindly under its protection, with which washing with water does not interfere. Another surgical purpose to which it has been applied is to obviate the erections attendant on gonorrhoea; the whole organ being enveloped in a coating, which renders expansion impossible. (See Am. Journ. Med. Sci., N. S., xxvi. 518.) it has been used in other cases, to prevent motion, and thus answer the purposes of splints. A casing for inflamed joints might sometimes prove useful in this way, and possibly also on the protective principle; but the method should be avoided in severe and acute cases.

Collodion has also been considerably used for the cure of superficial inflammation. Thus, it has been highly recommended in erysipelas and various cutaneous eruptions, in which it is supposed to operate partly by emptying the blood-vessels through compression. I believe that the benefit accrues much more from the complete exclusion of the air; and, indeed, the compression has sometimes provoked an increase of the disease by the irritation of the surrounding skin. Dr. Christen, assistant physician to the hospital at Prague, derived no permanent advantage from it in erysipelatous inflammation associated with fever; but found it of decided advantage in that affection when of purely local origin, proceeding from wounds, etc. The same writer tried it in the early stage of small-pox, with the view of checking the progress of the eruption in the face; but, though used under the most favourable circumstances, it failed to produce the desired effect. (ibid., xxv. 418.) it has been employed also in chilblains, and is supposed, applied thickly over the surface, to have aided in the discussion of buboes, and in the cure of swelled testicle. Mixed with half its bulk of castor oil, it is said to form an excellent dressing for burns and scalds. The compression it produces renders it sometimes efficient in the suppression of hemorrhage, and it has been recommended for this purpose in leech-bites. it may be used, moreover, for giving a lining to carious excavations in teeth, in order to protect them from the air. its efficiency has been supposed to extend even to internal inflammation; and the cure of an alarming case of puerperal peritonitis has been ascribed to the application of a layer of collodion over the whole surface of the abdomen. (M. Latour, L' Union Medicate, No. 3.) it is most conveniently applied by a brush. The modified solution, before described, should be preferred in the treatment of inflammatory affections of the skin.

Caoutchouc and Gutta Percha have properties similar to those of collodion, and may be used for the same purposes. By taking advantage of their solubility in chloroform, solutions of them may be made, which, when applied in thin layers, very quickly leave pellicles on the surface, having the impermeability of that of collodion, without the same rigidity. Such solutions have been considerably used in cutaneous affections. That of gutta percha is generally preferred. it may be used in all kinds of chronic cutaneous eruptions, especially in the scaly affections, and the advanced stages of eczema. it will often prove useful in the acute eruptions, though less applicable to cases in which there is watery or puruloid secretion. in erysipelas it is said to have been used beneficially, and has the great advantage over collodion, that it does not equally irritate by compression. Success, too, is claimed for it in rendering the eruption in small-pox abortive. in fact, it may be used in all cases of superficial inflammation and slight injuries, in the treatment of which the protective principle is applicable. Dr. Graves, of Dublin, bears special testimony in its favour as a remedy in cutaneous diseases; and I have myself employed it with the most satisfactory results. An investing layer of this kind might even be tried about the knees and larger joints, affected with obstinate rheumatism, or other chronic inflammation. A closely fitting and adhering coat of caoutchouc is thought to have proved useful in such cases.

The solution in chloroform should be saturated, and the application made by means of a camel's-hair pencil, which, on each occasion, should be immersed in boiling water, to prevent its becoming clogged by the solidified material. The application should be repeated as often as may be necessary to keep the covering complete. in the scaly and scabby affections, the skin should be first cleared, if possible, by poulticing, etc.

A solution of this kind is now officinal, under the name of Solution of Gutta-percha (Liquor Gutta-perch;e, U. S.). it is prepared by dissolving a troyounce and a half of gutta-percha in twelve troyounces of chloroform, and then decolorizing the liquid by agitating with it two troyounces of carbonate of lead previously mixed with five troyounces of chloroform, and setting the mixture aside for ten days or more, in order that the undissolved matter may subside. For directions in reference to the manipulation of the process, so as to obtain a clear solution, see the U. S. Dispensatory (12th ed., p. 1204).