• Experimental allergic encephalomyelitis is a disease of cell-mediated immunity and can be transferred passively to virgin recipients by lymphoid cells from sensitized donors. The rabbit eye contains myelinated medullary rays that can be visualized ophthalmoscopically. Intraocular injection of autologous lymph node cells from myelin basic protein (BP)-immunized rabbits into the vitreous leads to readily visualized optic neuritis while injection of cells from adjuvant immunized control rabbits does not. Microscopical study confirmed the presence of myelin destruction in recipients of cells from BP-sensitized donors. This eye chamber technique provides a simple model for the study of demyelination in vivo under direct observation.