Gunter von Hagen.
He 'plastinated' corpses, that is basically replaced all the tissue with plastic, apparently it even holds up to being analysed with an electron microscope.
I saw his exhibit when it came to London. It was very interesting from a scientific viewpoint, but also somewhat ghoulish in that anything like that attracts a certain amount of 'freakshow' status.
The horse and man thing was intended to demonstrate the vast size difference between a man and a horse, particularly how much more muscular a horse is, and yet the human brain is proportionately much larger.
Much controversy over the whole exhibit and a I believe it was eventually banned from Britain, although I think his public autopsies had a big effect on that. Earlier this year he did a late night series on channel 4 in which he dissected bodies (donated for that purpose) in front of a studio audience.
I found the specimens that had this substance injected into the blood vessels and then had all the flesh and bone rendered away to only leave a representation of the network of vessels the most interesting.