FRAGMENT FROM NATURE concludes this weekend on the continuation of the historical vignette about the development of the smallpox vaccine in the west. An equally interesting history could be told about its very early development in China and India. This history shows that the development of medical advances can, at times, be based on flimsy evidence, uncontrolled experiments, apples-and-oranges source materials, a degree of quackery mixed with obsession, and a decidedly zig-zag path. But despite this, these advances can occur.