II. Influence of Lactic Acid on Transplanted Tumors.

Abstract

Continuing our work on the action of lactic acid on various kinds of organisms we carried out a series of experiments on the effect of lactic acid on the growth of transplanted Sarcoma 39 in white rats∗ and of transplanted Sarcoma Rous in chickens.†

White rats were injected daily with lactic acid previously neutralized with sodium hydroxide to a pH ranging between 5 and 7 with doses of lactic acid ranging between 0.1 gm. and 0.3 gm. per kg. of body weight. These injections were made subcutaneously at a distance from the tumor and they were begun when the Sarcoma had reached the size of 0.5 to 1.0 square centimeters. This series of experiments was carried out with 90 rats having transplanted tumors, 28 of which served as controls. The size of the tumor in each case was measured with a compass and a ruler. The injections of lactic acid neutralized to pH of from 5 to 7 did not produce any ulcerations in rats. The injections of a lactic acid preparation with a pH 3 as well as of solutions of lactic acid in distilled water with a pH below 3 produced ulcerations of the tumors and the overlying skin. At the end of the experiments the control rats had tumors with an average size of 11.2 square centimeters, while those treated with lactic acid had an average size of only 3.0 square centimeters. The percentage of complete disappearance of Sarcoma 39 under these conditions was 50%. In the above mentioned control rats we did not observe spontaneous disappearance of tumors.

Another series of experiments with Sarcoma 39 was carried out in which 3 out of 10 control tumors spontaneously retrogressed and 22 out of 28 treated tumors disappeared.