JF Ptak Science Books Quick Post
"For this condition, I will prescribe, for your information, a marvelous cure, the result of my experience in such cases. Take a precious stone we call sapphire. Powder it most thoroughly in a metal mortar and store it in a golden vase. Put a little into the patient's eye every day and he will soon be cured "-- from the Medieval medical text De Oculis, by Benevenutus Grassus, Stanford University Press, 1929, page 58.
Admittedly I was more interested in the illustrations in this work1 than the text, mainly (and obviously) because the images are so striking. The text is in its way a pre-scientific attempt at 'curing" color blindness, which is a genetic disorder. The color wheels ("variable speed rotary color vision stimulator") were intended to be rotated to produce different color senses for "color vision stimulation"--it could be used to determine whether or not color vision was being "improved".
Most of the work was a sales vehicle for Dr. Newton's color blindness color regenerators, or whatever, all of which could be obtained from his office in Oakland. I guess Dr. Newton was trying, but...