Professor Sherman1 has pointed out that by the time a professional man has finished his schooling about one third of his life has passed; another third will be spent in proving to himself and others what he is able to do, and in most cases not until about the age of 50 does he attain or is he promoted to a post of high responsibility and given the fullest opportunities to do his work.This statement is in general true also for civil servants and men in the armed forces and in industry.