Moreau's vivisected Beast Folk revert after death
Edward Prendick, shipwrecked in 1887, is left on a Pacific island where Doctor Moreau surgically reshapes pumas, hyenas, swine and other animals into speaking, upright Beast Folk and drills them in a chanted Law ('Not to go on all-fours; that is the Law. Are we not Men?'). After the Leopard Man tastes blood and the puma-woman kills Moreau, the Law loses its enforcer, and over months the Beast Folk lose speech, drop to all fours and turn predatory. Prendick escapes and returns to London unable to stop seeing the beast beneath his fellow humans.