THE PAROTID, like other salivary glands, is the site of origin of a variety of tumors. Such lesions, though of various types, benign and malignant, are for the most part rare, with the exception of mixed tumors and carcinomas. The latter are the subject of this discussion. Since the first description of mixed tumors of the parotid by Virchow1 in 1863 the origin and classification of salivary gland tumors, both benign and malignant, has been disputed by pathologists throughout the world. Because of the presence of cartilage in some tumors, Virchow spoke of them as "diffuse enchondromas" and thought them to be of mesoblastic origin. With the finding of epithelial elements, however, the composite nature of the tumors became evident to him, and he first used the term "Zusammengesetze Geschwülste" or mixed tumors. In 1877, Cohnheim2 suggested that in an early stage of embryonic development more cells are produced than are required and a number of unappropriated