Everyone confesses in the abstract that exertion which brings out all the powers of body and mind is the best thing for us all; but practically most people do all they can to get rid of it, and as a general rule nobody does much more than circumstances drive them to do.
Bio: Leonard Hayflick was an American anatomist who was Professor of Anatomy at the UCSF School of Medicine, and was Professor of Medical Microbiology at Stanford University School of Medicine.
