Document zQmvzbaQLVnMqebM1YmOxDrqm

TUMORS OF THE SKIN 143 Tsutsui, H., Gann. 12: 17, 1918. Twort, C. C., and Twort, J. M., Ztschr. f. Krebsforsch. 32: 491, 1930. Twort, J. M., and Twort, C. C., Am. J. Cancer 23: 52, 1935. Ulesco-Stroganova, K., Ztschr. f. Krebsforsch. 25: 394, 1927. Ullmann, K., Krebsentwicklung als Folge beruflichgewerblicher Hautschadigungen, in Op- penheim, M., Rille, J. H., and Ullmann, K., Die Schadigungen der Haut durch Beruf und gewerbliche Arbeit, Vol. Ill, p. 202, Leopold Voss, Leipzig, 1926. Uytdenhoef, Arch. med. soc. et d'hyg. 2: 830, 1939. Vaughan, K., Brit. M. J. 2: 495, 1925. Veiel, F., Arch. f. Dermat. 148: 142, 1924-25. Vles, F. de Coulon, A., and Ugo, A., Arch, de phys. biol. 9: 209, 1932. Voltz, Monatschr. f. Krebsbekampf. 6: 86, 1938. Vossenaar, A., Nederl. tijdschr. v. geneesk. 67: 7B, 1686, 1923. de Vries, W. M., Pitch Cancer in the Netherlands. Rep. International Conference on Cancer, London, p. 290, 1928, Bristol, John Wright & Sons, Ltd. Warnes, A. R., Coal Tar Distillation. 2nd. ed. London, 1917. Watson, A. F., J. Path. & Bact. 34: 301, 19315 36: 251, 1933. Cancer Rev. 7: 445, 1932. Am. J. Cancer 25: 753, 1935. Weiss, M., Beitr. z. klin. Chir. 154: 153, 1931. Wells, H. G., Am. J. Cancer 15: 1919, 1931. Wieder, L. M., Arch. Dermat. & Syph. 25: 624, 1932. Woglom, W. H., Arch. Path. 2: 533, 708, 1926. Woglom, W. H., and Herly, L., J. Cancer Research 13: 367, 1929. Wood, H. B., J. Cancer Research 13: 54, 1929. Yamaciwa, K., Gann. 18: 1, 1925. Yamagiwa, K., and Itchikawa, K., Mitt. d. med. Fak. d. kais. Universitat zu Tokio 15: 295, 1916. Yamagiwa, K., and Saigusa, G., Gann. 22: 10, 1928. Yamacuchi, J., Nishiyama, Y., and Suzuki, T., Zentralbl. f. allg. Path. u. path. Anat. 40: 93, 1927. Zenker, R., Ztschr. f. Krebsforsch. 28: 121, 1929. Zweig. Uber einen Fall von multiplem Hautcarcinom bei einem Brikettarbeiter. Inaug. Diss. Berlin, 1909. Zweig, cited by Leymann, Zentralbl. f. Gewerbehyg. j: 2, 19x7. c. Fractionation and Distillation Products of Mineral Oils, Oil Shales, Lignite, and Coal Tar (Processed Oils and Paraffins) I. CHEMICAL AND TECHNOLOGICAL ASPECTS Semi-refined and refined oils and paraffins are products of the fractionation and distillation of petroleum, oil shales, lignite, coal tar, and of the cracking of coal. Their chemical composition depends upon and varies with the original substances they are prepared from, and with the methods by which they are obtained (refining processes). Petroleum Oils. Crude mineral oil is separated into several fractions by distillation at various temperatures. The volatile gasoline is driven out of the crude mineral oil at a temperature ranging from 90C to 200C. The next fraction, kerosene, is obtained when the contents of the still are heated to approximately 2$oC. The residue; is subjected to a temperature up to 3QOC. gas oil is distilled off. What is left at the bottom of the still, represent-