metaplasia of the glandular epithelium to stratified squamous epithelium with occasional malignancy. An investigation of the histogenesis of tumors of the salivary glands by Steiner (16) produced a comprehensive work

This experimental work was undertaken to study the effects of various carcinogens on salivary glands in the hope of producing primary epithelial neoplasms, and, among these, the so-called “mixed tumors― of the parotid and submaxillary glands. Indeed, this study has been stimulated by the meager results obtained in this field by a few authors and the uncertainty concerning the origin and pathogenesis of these epithelial tumors of varied patterns. Additional work will be described at a later date on the transplantability of the neo plasms obtained and the tumor development, un der various conditions, which altered the physio logic activity of the glands prior to and following the introduction of various carcinogens. Löwenstein (8), in 1910, injected scarlet red oil into the parotid glands of rabbits and produced in