Experimental inhibition of carcinoma by lymphosarcoma.

been deliberately omitted from consideration. Of patients who die of malignant lesions, 2 to 4 per cent disclose multiple primary malignant lesions. From reports which do include the lymphomas, it is ap parent that the combination of carcinoma with a lymphosarcoma is extremely rare. Warren and Gates (9) studied 794 cases of mul tiple primary malignant lesions. Ten of these were of carcinoma associated with lymphosarcoma. Owen (6), in a study of 143 multiple malignant le sions, did not record a single association of the two types of neoplasm. Schreiner and Wehr (7) reported 307 cases of multiple primary malignant lesions, 4 of which showed a lymphosarcoma coupled with a carcinoma. Burke (1) analyzed data on 27 cases of primary multiple malignant lesions, none of which were associated with lymphosarcoma. The same was true for the 25 cases detailed by Kirshbaum and Shively (3). Furthermore, the infrequency of metastatic in volvement of the spleen by a carcinoma is a clini cal observation which is pertinent to our inquiry. Willis (10) has stated that the incidence of splenic metastasis in malignant lesions which have come to necropsy has ranged from 1 to 4 per cent. Experimentally, the controversial literature dealing with this presumed antagonism between the spleen and other lymphatic structures on the one hand, and the growth of a carcinoma on the other, has been reviewed by Woglom (11). In his study of 600 papers dealing with resistance to transplantable tumors, the role of the lymphocytes was extensively cited. It was shown by some that the development of immune reactions to trans planted tumors was always associated with the