A peculiar cellular condition resembling that found in amaurotic idiocy but limited almost exclusively to the external geniculate body has been observed recently by Spielmeyer. I have made a search for such cells in a large number of cases, with the results to be reported in this paper. The condition is a type of pigment atrophy and therefore occurs most frequently in old age. The study involved consideration of the amount of lipoid pigment in nerve cells, a problem originally investigated by Obersteiner1 in 1903. Curiously, Obersteiner did not include the cells of the external geniculate body in his work.
MATERIAL AND METHODS
Although the external geniculate body is not sectioned as a routine at the Deutsche Forschungsanstalt für Psychiatrie, it was possible to find suitable sections in about one hundred and fifty cases from the collected material. In most cases the sections were from only one side. Specimens