(1834â1908), Dutch ophthalmologist. Snellen was director of an eye clinic at Utrecht. In 1862 he introduced a test for measuring the acuteness of vision which consisted of printed letters or words in type of various sizes.
The poppy of wartime remembrance is Papaver rhoeas, the red-flowered corn poppy. This poppy is a common weed in Europe and is found in many locations, including Flanders, which is the setting of the famous poem In Flanders Fields by the Canadian surgeon and soldier John McCrae.
Rules for the legal cultivation of opium poppies were set out in the United Nations' Single Convention on Narcotic Drugs in 1961. Countries that produce and export opium must keep a close watch on the poppy farms within their borders. In Turkey, for example, poppy farmers harvest both the opium and the seeds.