While Neumann and coworkers have demonstrated protease-resistant synuclein using a special technique, referred to as the histoblot (9), a similar phenomenon is also apparent with conventional immunohistochemistry, as demonstrated in two adjacent paraffin sections of the basal forebrain from a patient with Lewy body disease, immunostained for synuclein with no pretreatment or after pretreatment with proteinase K. The protease-resistant synuclein, especially within neuritic processes, becomes evident after protease treatment, while the more diffuse punctate synaptic staining that represents normal synuclein is diminished by the treatment.