Abstract
A histochemical study was made of 13 cases of lipidoses of the central nervous system. Niemann-Pick''s disease can be differentiated from other cerebral lipidoses by the finding that all affected cells store histochemically stainable phospholipids. Evidence has been adduced indicating that the material stored in infantile amaurotic idiocy is a complex containing ganglioside, cholesterol, and possibly other constituents. The non-infantile forms of amaurotic idiocy were found to differ in essential points from the classical infantile form.