Our knowledge of pernicious anemia is being constantly enriched, especially our knowledge relating to the changes occurring in the nervous system. And justly so, because after all, next to the blood changes, the most characteristic and frequent clinical findings are on the part of the central nervous system. Minnich† (1893) demonstrated lesions in the spinal cord in approximately 70 per cent, of cases of pernicious anemia. Of forty-one cases treated by Billings (1900), forty showed neurological symptoms. In a very recent (1919) report of the 150 moderately advanced cases of pernicious anemia examined at the Mayo Clinic, Woltman found indisputable evidence of nervous tissue disintegration in over 80 per cent.
Formerly the neuropathology of this disease consisted chiefly in descriptions of the changes taking place in the spinal cord. It has been but comparatively recently that investigation has shown that these changes are not limited to the cord, but involve