In reviewing the literature in an attempt to identify the condition in the case which we are here reporting, we have found that Letterer,1in 1924 under the title "Aleukamische Retikulose (Ein Beitrag zu den proliferativen Erkrankungen des Retikuloendothelialapparates)," described the occurrence of splenohepatomegaly, associated with anemia, and a purpuric eruption in a 6 month old infant. The child died four days after admission to the hospital, and at autopsy the histologic examination revealed a unique and surprising condition. In the liver, spleen, lymph nodes, bone marrow and skin there was a proliferation of large, pale reticulo-endothelial cells, invading and replacing the normal structure of these.organs. Following the publication of Letterer's article, several quite similar cases were reported, but it was not until 1933 that Siwe,2in describing a similar case in a 16 month old infant in an article entitled "Die Reticuloendotheliose—ein neues Krankheitsbild unter den Hepatosplenomegalien,"