In a recently published monograph on the microscopic changes in the heredosystemic diseases, K. Schaffer again states with emphasis that family amaurotic idiocy is an ideal example of a systemic heredodegeneration.1It is well characterized as to ontogenetic origin and as to blastodermic, systemic and segmental localization. The blastodermic localization is shown by an elective degeneration of only ectodermal tissue, histologically represented by the swelling of the hyaloplasm, which at a later stage is replaced by granular precipitations. At the first stage, the prelipoid, the ganglion cells do not stain with fat stains, but in most of the cases they do stain with hematoxylin; at the second, the lipoid stage, which corresponds to the late infantile and juvenile cases, the granular precipitations within the ganglion cells can be stained with sudan and scarlet red. The process of swelling is distributed throughout the nervous system and reveals itself by extreme