Alfred North. 1861--1947, English mathematician and philosopher, who collaborated with Bertrand Russell in writing Principia Mathematica (1910--13), and developed a holistic philosophy of science, chiefly in Process and Reality (1929)
A tiny epidermal cystlike mass with a narrow or obstructed opening on the skin surface, which may rupture, caused by the retention of secretions of a sebaceous gland. Also called closed comedo.