he would never have based a course of treatment on it , but you could tell a man who 'd had a hip replacement six months ago from one currently suffering with hemorrhoids simply by the way he walked ; you could tell a neck strain by the way a woman would turn her whole body instead of just looking back over her shoulder ; you could tell a kid who 'd picked up a good crop of lice at sujnmer camp by the way he kept scratching his head .