Collodion

Syn. Plain collodion. The following are the best methods of preparing plain collodion for surgical purposes:— Prep. 1. (Ph. U. S.) Nitrate of pota a, in powder, 10 oz.; sulphuric acid, 8 1 ⁄ 2 fl. oz.; triturate together in a wedgwood mortar until uniformly mixed; then add of fine carded cotton (free from impurities), 1 ⁄ 2 oz.; and by means of the pestle or a gla rod, saturate it thoroughly with the liquor for a period of about 3 or 4 minutes; next transfer the cotton to a ve el containing water, and wash it in succe ive portions of pure water, with agitation and pre ure, until the washings cease to affect litmus paper or a solution of chloride of barium; it is then to be spread out and dried by a very gentle heat, and di olved by agitation in a stoppered bottle with rectified sulphuric ether, 1 quart, to which rectified spirit (alcohol), 1 fl. oz., has been previously added. 2. (Mialhe.) Nitrate of pota a, 40 parts; concentrated sulphuric acid, 60 parts; carded cotton, 2 parts; proceed as last until the dry cotton is obtained, then take of the prepared cotton, 8 parts; rectified sulphuric ether, 125 parts; mix in a well-stoppered bottle, and agitate it for some minutes; then add gradually, rectified alcohol, 1 part; and continue to shake until the whole of the liquid acquires a syrupy consistency. It may be now pa ed through a cloth; but a better way to prevent lo is to let it repose for a few days, and then decant the clear portion. 3. (Lauras.) This proce only differs from No. 2 in the following particulars:—The cotton is immersed for 12 minutes, then rinsed 2 or 3 times in cold water, and afterwards immersed in a solution of carbonate of pota a, 4 parts, and water, 200 parts. Lastly, it is plunged again into simple water, and dried at a temperature of 77° to 86° Fahr. 4. (B. P.) Pyroxylin, 1 part; rectified spirit, 12 parts; ether, 36 parts; mix the ether and spirit, and add the pyroxylin. Keep in a well-corked bottle. 5. (Parrish.) Thoroughly saturate clean carded cotton, 1 ⁄ 2 oz., with fuming nitric acid and sulphuric acid, of each 4 fl. oz., previously mixed and allowed to become cool; macerate for 12 hours; wash the cotton in a large quantity of water; then free it from the water by succe ive washings in alcohol, and di olve in ether, 3 pints. Obs. For succe in the manufacture of collodion it is absolutely nece ary to avoid the presence of water. The ordinary commercial oil of vitriol, sp. gr. 1·84, may be used. Profe or Procter, of Philadelphia, gives preference to the proce with the mixed acids (No. 5), and directs that the cotton should be allowed to macerate for four days. In drying the cotton great care should be taken to prevent an explosion. Uses, . In surgery plain collodion is employed as a dre ing for wounds, and as a protection to abraded surfaces. On drying, it unites the former closely, and preserves the latter from the action of the air. It is impervious to water, and being transparent, it admits of the progre of the wound being inspected when nece ary. Such is its adhesive power, that a piece of cloth cemented with it to the dry palm of the hand will support a weight of 25 to 30 lbs. The parts to which it is applied should be freed from moisture. See Collodions , Coloured , Elastic , Medicated and Vesicating ( below ).