4000 YEARS of MEDICINE £ M 2000 BC : Here, eat this root. ■ 1000 AD : That root is heathen! Here, say this prayer. 1865 AD : That prayer is superstition! Here, drink this potion. 1935 AD: That potion is snake oil! Here, swallow this pill. 1975 AD: That pill is ineffective! Here take this