In rats whose intestinal or thoracic duct lymph was drained externally for several days, lymphopenia occurred. Large numbers of cells were collected in the lymph each day, as many, apparently, from the intestinal lymph alone as from the thoracic duct. Hepatic lymph contributed relatively few cells.
Augmentation of lymph flow decreased the concentration of cells in the lymph but did not affect the total number of cells collected each day. Fasting for several days likewise did not decrease the first day’s output. With each day’s lymph flow, however, the daily output of cells spontaneously decreased. The decrease was not prevented by the intravenous injection of fresh lymph or of fresh rat plasma in large amounts. In view of this unexplained effect, one must be cautious in interpreting the results of experiments on the lymph lymphocyte.