Progressive multifocal leukoencephalopathy (PML) 6.8 De Vivo disease 6.9 Alzheimer's Disease 6.10 HIV encephalitis 6.11 Rabies 7 See also 8 References [ edit ] History Paul Ehrlich was a bacteriologist studying staining , a procedure that is used in many microscopic studies to make fine biological structures visible using chemical dyes. When