Abstract
Summary.: The phosphomonoesterase activities of regenerating rat's liver after lobectomy has been estimated at pH 4.8, 5.2, 6.1 and 9.5. From the liver‐weight at death and the calculated liver residue on operation the total number of enzyme units produced during regeneration is calculated. The acid phosphatases essentially regenerate parallel to the liver mass. The alkaline esterase increases enormously, four fold already on the first day, and it reaches a maximum on the second day at 700% of the starting value. A functional relationship between the regeneration process and the phosphatases is assumed.