Whichever process is used, it is customary to give the bleached skins a subsequent “blueing,” by passing them through a very weak solution of a blue or violet dye, such as indigo-carmine, crystal violet, alkali blue or ultramarine. The furs are then dried and finished off as usual. In drum cleaning white furs, gypsum or white sand, or sometimes even talc are used with the sawdust, or occasionally alone without the sawdust. BIBLIOGRAPHY Allen “Commercial Organic Analysis” Armour, B. R. “Fur Dressing and Dyeing” 1919 ---- Color Trade Journal, Vol. 1, p. 51–53 ---- Jour. Amer. Leather Chemists’ Assn., Vol. 13, p. 63–69. Belden, A. L. “Fur Trade in America” 1917 Beltzer, F. J. G. “Industrie des Poils et Fourrures, etc.” 1912 ---- Revue Generale des Matieres Colorantes, Vol. 12, 1908 Bennett, H. G. “Manufacture of Leather” 1910 Bertram, P. Deutsche Färber-Zeitung 1895–96 Heft 17, p. 266 Bird, F. J. “American Practical Dyers’ Companion” p. 241–245 Boerner, H. Kunststoffe, 1912 p. 223 Brevoort, H. L. “Fur Fibres as shown in the Microscope” 1886 Bucher, B. “Geschichte der technischen Künste” 1875–1893 Cubaeus, P. “Das Ganze der Kürschnerei” 1912 Davis, C. T. “Manufacture of Leather” Erdmann, E. Deutsche Färber-Zeitung 1894–95 Heft 21, p. 337 ---- Zeitschrift für angewandte Chemie, 1895, Heft 14 ---- Zeitschrift für angewandte Chemie, Heft 35, 1905 ---- Berichte, 1904, 37, p. 2776, 2906 Farrell, F. J. “Dyeing and Cleaning” 1912 Fleming, L. “Practical Tanning” 1916 Fougerat, L. “La Pelleterie dans l’antiquité, la préhistoire, etc.” Gardner, W. M. “Wool Dyeing” 1896 Grandmougin, E. Zeitschrift für Farben-Industrie, 1906, 5, p. 141 Gruene, E. Deutsche Färber-Zeitung, 1895–96 Heft 13, p. 197 Halle “Werkstätte der heutigen Künste,” 1762, Vol. 2, p. 317 Hartwig, O. L. “Sprengler’s Künste und Handwerke,” 1782 Hausman, L. A. Scientific Monthly, Jan. 1920; March, 1921 ---- Natural History, Vol. 20, 4, 1920 ---- American Journal of Anatomy, Sept. 1920 ---- American Naturalist, Nov.–Dec. 1920 Hayes, A. H. National Cleaner and Dyer, Nov. 1920, p. 55–57 Jacobson, “Schauplatz der Zeugmanufacturen” p. 493 Jones, J. W. “Fur Farming in Canada” 1913 Knecht, Rawson & Loewenthal “Manual of Dyeing” 1916 Kobert, R. “Beitrage zur Geschichte des Gerbens und der Adstringentien” 1917 Koenig, F. Zeitschrift für angewandte Chemie, 1914, Vol. 1, p. 529 Lamb, J. W. Jour. Soc. Dyers & Colourists Dec. 1905, p. 323 Lamb, M. C. “Dressing of Leather” 1908 ---- Jour. Soc. Dyers & Colourists 1913, 29, p. 160–165 Larish & Schmid “Das Kuerschner Handwerk” 1–3 Laut, A. C. “The Fur Trade of America” 1921 Lightfoot, J. “The Chemical History & Progress of Aniline Black” 1871 Mairet, E. M. “A Book on Vegetable Dyes” 1916 Martin, G. “Industrial Organic Chemistry” Matthews, J. M. “Application of Dyestuffs” 1920