The sheep dog says to the farmer, “Here are your 20 sheep.”
The farmer says, “but I only have 17 sheep.”
“I know,” says the sheep dog, “I rounded them up.”
OphthalmoscopeIn 1850, Hermann von Helmholtz (1821-94) announced his invention, the ophthalmoscope, to the Berlin Physical Society. His description Beschreibung eines Augenspiegels zur Untersuchung der Netzhaut im lebenden Auge (An Eye mirror for the Investigation of the Retina of the Living Eye) was published in Oct 1851. Using his invention he looked through one side of a glass plate while light was reflected into the subject's eye from the other. It revolutionized ophthalmology, enabling a view inside a person's eye to see the details of the living retina, diagnose eye diseases and prevent blindness. It pioneered endoscopy, making new information available in a way as dramatic as the invention of the telescope or micrscope opened new vistas.* |
