I probably shouldn’t be telling this story. It starts in 1968. According to (brilliant) researcher, surgeon and writer Atul Gawande, in that year, The Lancet published findings that represent one of the most important medical advances of the last century. It was just this: David R. Nalin and Richard A. Cash, American researchers in Dhaka during a cholera outbreak, added sugar to salt and water hydration and administered it orally to 29 patients. Cholera deaths: zero. Sugar, it seems, helps the gut absorb fluids. Cholera pandemics killed millions in the nineteenth century. Even after intravenous fluids reduced mortality to 30 per cent in the early years of the twentieth century, globally, most people died, especially in places where...

Who could have imagined, even a few years ago, that holding a fingertip to your mobile phone screen would tell you your blood pressure? Yet, today, you can buy any one of a number of apps that does just that. There’s only one problem. You’re most likely not getting an accurate blood pressure reading. “Not ready for prime time,” is how Dr. Nilay Kumar described the technology to Reuters Health last month. Kumar is an attending physician at the Cambridge Health Alliance in Cambridge, Mass., and a Harvard Medical School instructor. He’s lead author on a study that analyzed the top 107 apps for “hypertension” and “high blood pressure”. Most – about 75 per cent – were found to...