Several years ago, one of us1in reporting three cases of lipoid histiocytosis (Niemann-Pick's disease) emphasized the striking clinical and anatomic differences between this condition and Gaucher's disease. Niemann,2in 1914, reported a peculiar disease in a baby girl of 18 months which he thought had some points of resemblance to Gaucher's disease but was clinically unlike this condition. He called it "ein unbekanntes Krankheitsbild." Shortly after this, Knox, Wahl and Schmeisser3reported two cases quite similar to that of Niemann. These authors believed that they were dealing with cases of Gaucher's disease in infants. Mandlebaum and Downey4showed quite clearly, however, that the cases reported by Knox, Wahl and Schmeisser had very few points of resemblance to, and were in reality quite different from, Gaucher's disease. Siegmund5reported another case of what he thought was Gaucher's disease in an infant. Pick6showed that