Check out this ophthalmotrope, found at Harvard’s Putnam Gallery!
(photograph by the blogger)

The device, which served to demonstrate muscular control of ocular vision, was made by Max Kohl in Germany at around 1893. The device consisted of lead weights on strings, which could be pulled to show movements of the muscles that bring the eyeballs together.

At this time, refrigeration was not widely used yet, so cadavers reeked too much for anatomy students to work with. Instead, machines like these offered an alternative way to interactively teach anatomical details. We’ve sure come a long way since 1893… all thanks to formaldehyde!