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COLLODION (from the Gr. &M a' , glue)

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Originally appearing in Volume V06, Page 694 of the 1911 Encyclopedia Britannica.
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COLLODION (from the Gr. &M a' , See also:glue)  , a colourless, viscid fluid, made by dissolving See also:gun-See also:cotton and the other varieties of pyroxylin in a mixture of See also:alcohol and See also:ether . It was discovered in 1846 by See also:Louis See also:Nicolas Menard in See also:Paris, and independently in 1848 by Dr J . Parkers See also:Maynard in See also:Boston . The quality of See also:collodion differs according to the proportions of alcohol and ether and the nature of the pyroxylin it contains . Collodion in which there is a See also:great excess of ether gives by its evaporation a very tough film; the film See also:left by collodion containing a large quantity of alcohol is soft and easily torn; but in hot climates the presence of an excess of alcohol is an See also:advantage, as it prevents the rapid evaporation of the ether . Under the See also:microscope, the film produced by collodion of See also:good quality appears translucent and colourless . To preserve collodion it should be kept cool and out of the See also:action of the See also:light; iodized collodion that has been discoloured by the development of See also:free See also:iodine may be purified by the See also:immersion in it of a See also:strip of See also:silver See also:foil . For the iodizing of collodion, ammonium bromide and iodide, and the iodides of See also:calcium and See also:cadmium are the agents employed (see See also:PHOTOGRAPHY) . Collodion is used in See also:surgery since, when painted on the skin, it rapidly dries and covers the skin with a thin film which contracts as it dries and therefore affords both pressure and See also:protection . Flexible collodion, containing See also:Canada See also:balsam and See also:castor oil, does not crack, but, on the other See also:hand, does not See also:contract . It is therefore of less value . Collodion is applied to small aseptic wounds, to small-pox pustules, and occasionally to the end of the urethra in boys in See also:order to prevent nocturnal incontinence .

Collodion and crystals of carbolic See also:

acid, taken in equal parts, are useful in relieving toothache due to the presence of a carious cavity . Vesicating or Blistering Collodion contains cantharidin as one of its constituents . The styptic colloid of See also:Richardson is a strong See also:solution of See also:tannin in gun-cotton collodion . Similarly collodion may be impregnated with salicylic acid, carbolic acid, iodine and other substances . Small balloons are manufactured from collodion by coating the interior of See also:glass globes with the liquid; the film when dry is removed from the glass by applying suction to the mouth of the See also:vessel . M . E . Gripon found (Conipt. rend., 1875) that collodion membranes, like glass, reflect light and polarize it both by See also:refraction and reflection; they also transmit a very much larger proportion of radiant See also:heat, for the study of which they are preferable to See also:mica .

End of Article: COLLODION (from the Gr. &M a' , glue)
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