A history of medicine.

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 ... mutation. Here, take this tetracycline."

1960 to 1999 a.d. - Thirty-nine more mutations. "Here, take this more powerful antibiotic."

2000 a.d. - The bugs have won. "Here, eat this root."

Anonymous, quoted in "Overcoming Antimicrobial Resistance", World Health Report on Infectious Disease, 2000.