Changes in the livers of mice after administration of 3:4:5:6-dibenzcarbazole

THE known carcinogenic hydrocarbons produce primary tumours at the site of application [cf. Cook et al. 1937] and one of them at any rate (1:2:5:6-dibenz- anthracene) increases the incidence of lung cancer in those strains of mice in which this condition occurs spontaneously [Lynch, 1935; Andervont, 1935]. The feeding [Sasaki & Yoshida, 1935] or injection [Shear, 1937] of 4'-amino- 2:3'-azotoluene induces malignant changes in the livers of rats and mice. This compound, however, does not have any marked carcinogenic action at the site of administration. 3 :4:5:6-iDibenzcarbazole produces sarcomata as a result of subcutaneous injection into rats and epitheliomata and bile duct hylertrophy resembling cholangiomata when it is painted twice weekly on the skin of mice Strong et al. [1938] found that the injection of 3:4:5:6- dibenzcarbazole into mice of the C.B.A. strain, in which hepatoma occurs spontaneously, increased the incidence of these tumours.