If you're interested in the history of medicine, or if you just wonder what's so funny about the four humours, then this is for you: BBC Radio 4 has just started a 30-part six-week long series with medical historian Andrew Cunningham. The first broadcast starts with blood-letting, the Ancient Greeks, and the four humours (seen left). You can follow along with Radio 4 online weekdays at 3:45 p.m. GMT (9:45 a.m. Sask Time), although the BBC appears to be maintaining at least a weekly archive available upon demand. Check it out at: http://www.bbc.co.uk/radio4/science/medicine.