VIII. Headache and double optic neuritis (without localizing symptoms); probably syphilitic (recovery, with blindness, 2; with impaired vision, 4), 6. IX. Headache and double optic neuritis (without localizing symptoms); no evidence of syphilis; duration six and two and a quarter years, respectively. Termination still uncertain, 2. X. Headache and double optic neuritis (without localizing symptoms); no evidence of syphilis; recovery with blindness, 8; with impaired vision, 3; with good vision, 8, 19. The following are brief abstracts of the notes of the cases in Group X. which have come under our observation and which we have followed for a considerable period of time. The number of years during which each case has been followed is given in parentheses after the brief note. 1. A boy, aged ten years. Double optic neuritis, headache, and vomiting; slight internal strabismus of the left eye. Recovery with normal vision. (Seven years.) 2. A young woman, aged seventeen years. Headache, vomiting, and double optic neuritis. Recovery, but with impaired vision in one eye and blindness in the other. (Five and a half years.) 3. A young woman, aged eighteen years. Double optic neuritis, headache, and vomiting; several epileptic fits. Recovery, with useful vision in one eye; vision in the other is very defective. (Seven years.) 4. A young woman, aged eighteen years. Double optic neuritis, headache, and vomiting. Recovery, but complete blindness followed. (Four years.) 5. A young woman, aged nineteen years. Double optic neuritis, headache, and vomiting. Recovery with good vision. (Three years.) 6. A man, aged twenty years. Double optic neuritis, headache, and vomiting. Recovery, but complete blindness followed. (Two and a half years.) 7. A girl, aged ten years. Double optic neuritis, headache, and vomiting; knee-jerks were absent. Recovery, but complete blindness followed. (Three years.) 8. A boy at the age of thirteen years had double optic neuritis and headache; recovery ensued. At the age of fifteen years he had a return of headache and double optic neuritis; also vomiting. At a later date there was partial anæsthesia in the distribution of the right fifth cranial nerve; the right cornea was opaque; there was complete blindness in both eyes. Partial anæsthesia of the face and blindness remained, but otherwise the patient recovered and felt quite well nine months after the second attack. 9. A girl, aged sixteen years. Double optic neuritis, headache, vomiting; slight internal strabismus of the right eye. Recovery with normal vision. (Four and a half years.) 10. A boy, aged ten years. Double optic neuritis, headache, and vomiting. The head had increased in size. Recovery, but with complete blindness. (Three years.) 11. A woman, aged nineteen years. Double optic neuritis, headache, and vomiting. Recovery with normal vision. (Three years.)