A patient with bilateral chorioretinal lesions was followed for a seven-year period. He was studied intensively during two exacerbations of the inflammation in the right eye. The methylene blue dye test, done on several occasions, was always negative in a titer of 1:16 or greater. The patient died from a ruptured diverticulum during a period of activity of the chorioretinitis in the right eye. Multiple cysts containing Toxoplasma gondii were found in this eye. A methylene blue dye test later was repeated on stored frozen serum obtained during each exacerbation and was positive only in undiluted serum. Report of Case History. —A 42-year-old white ticket agent noted progressive loss of vision in the right eye commencing in 1951. The left vision first became blurred in April, 1956. He was referred to the Uveitis Clinic on May 31, 1956. The right vision measured 20/200 and the left 20/20. Heavy deposits of