1. The administration of emulsions of the anterior lobe of the ox pituitary increases very markedly the rate of growth of the primary tumor in rats inoculated with carcinoma. The growth of small tumors is accelerated relatively more than that of large tumors.
2. This acceleration is only evidenced, however, at a certain stage in the growth of the tumor, subsequent to the twentieth day succeeding inoculation. The administrations do not enhance the tendency of the tumors to metastasize.
3. Liver emulsion does not cause an acceleration of the growth of carcinomata in rats.