Enzymatic differences between short-lived and long-lived Drosophila strains.

The activities of acid and alkaline phosphatase were measured. The activity of acid phosphatase increased during the whole onto- genesis of both Drosophila strains studied--the short-lived vestigial and the long-lived white. This increase was more marked in the more rapidly ageing vestigial flies. The activity of alkaline phosphatase decreased in both strains of flies simultaneously from the larval stage to young imagos. A slight increase of the activity as in old vestigial as in adult white flies appeared.