Isopathy is a subform of homeopathy invented by Johann Joseph Wilhelm Lux in the 1830s. Rather than "like cures like" (which is based around symptoms), isopathy uses "the same thing cures the thing". i.e., isopathic preparations are made from the actual cause of the illness or its byproducts, such as pus. This pus remains highly diluted, of course. Most "homeopathic vaccines" are made this way, differing from normal vaccines by the potentisation process and the fact that live, rather than inactivated pathogens, are used.