"* 2000 B.C. – Here, eat this root
* 1000 A.D. – That root is heathen. Here, say this prayer.
* 1850 A.D. – That prayer is superstition. Here, drink this potion.
* 1920 A.D. – That potion is snake oil. Here, swallow this pill.
* 1945 A.D. – That pill is ineffective. Here, take this penicillin.
* 1955 A.D. – Oops....bugs mutated. Here, take this tetracycline.
* 1960-1999 – 39 more "oops"...Here, take this more powerful antibiotic.
* 2000 A.D. – The bugs have won! Here, eat this root."