A Scottish doctor's association with the discovery of the plague bacillus.

Plague killed at least a quarter of the population of Europe in 1348. This was the first wave of the epidemic known as 'The Black Death' which continued for two years and then recurred sporadically till the late 17th Century. In London in 1603, 22.6% of the population died from plague and in the outbreak known as The Great Plague of London in 1694 there were over 70,000 deaths out of a population of 460,000. Many English villages were completely wiped out at this time. Marseilles suffered severely in 1720. The next serious outbreak was in Canton in China in 1894, the disease spreading to Hong Kong. 80,000 died, the great majority of these being in China. A Scottish doctor played an important part in the management of this epidemic when it reached the British colony, and by chance found himself on the periphery of the controversy about who first discovered Yersinia Pestis, the Gram negative bacillus that causes plague.