Gutartige Riesenzellgeschwülste.

This is a small monograph on excellent paper with splendid illustrations in which an attempt is made to bring into a single group, to be known as benign giant-cell tumors, the simple epulides, the solitary giant-cell tumors of bone, and certain tumors of the skin and tendon sheaths which also contain giant cells. The result is not at all satisfactory. The author concludes that all these growths, which also include some xanthomas, possess in common an origin from mesenchymal tissue which has escaped complete differentiation into mature structures; that the giant cells also develop from this mesenchyme and later may disintegrate into single cells, and that the maturing of the original ground substance into giant cells, spindle cells and stroma is alike in all these growths. Views of different writers about the pathogenesis and histogenesis of these tumors are presented at length, including some consideration of American literature, but the