Yesterday I went with Peanut and Bad Mama to Philadelphia's Mütter Museum. It's a respectful museum devoted to medical anomalies, utterly fascinating if you like that sort of thing, which all three of us do.
I was deeply struck by a unique method of tissue preparation devised by Werner Spalteholz, not a name I was previously familiar with. One of the great German anatomists -- his Hand Atlas is still regarded as a classic -- he devised a method to render tissue transparent, which is still used to this day. The trick is to permeate the tissue with chemicals of the right index of refraction, such as oil of wintergreen, which 'clears' the tissue, like a grease spot on a paper placemat. You stain or dye the things you want to highlight, and they appear like a floating three-dimensional hologram in the preparation.
Spalteholz's method was used extensively in Dresden's German Hygiene Museum, the original home of the Transparent Man which freaked so many members of my generation out as children. Between Hitler trashing the Otto Dix murals, the Billy Pilgrim incident, and the Soviet aftermath, eighty percent of the museum was destroyed. Interestingly, the Soviets thought highly enough of the museum to rebuild it.
Spalteholz patented his method in the U.S. (#1021952), after being given an honorary doctorate at the University of Wisconsin a few years before.
Not a whole lot of information on the history of this sort of innovation out there.