(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.
No, not all poppies contain opium; only one does. Among those flowers we call poppies, there are 11 genera in the subfamily Papaveraceae, and the most commonly considered poppy flowers belong to one of those genera which is the genus Papaver. In that genus, only one species contains opium, the breadseed or opium poppy (Papaver somniferum).