Hughes Bennett1 proposed the term leukocythemia and Virchow2 the term Leukämie almost simultaneously in 1845 to designate the disease which is now regarded almost uniformly by English speaking physicians as leukemia. Later two types were differentiated and called splenomyelogenous leukemia and lymphatic leukemia. Reschad and Schilling-Torgau,3 in 1913, described a third common type, monocytic leukemia. A number of other types of leukemia or related disorders are reported on frequently in the medical literature, among these being chloroleukemia, leukosarcoma, plasma cell leukemia, eosinophilic leukemia, basophilic leukemia, megakaryocytic leukemia, leukanemia, pseudoleukemia, aleukemic leukemia and others to be mentioned later.
There has been a tendency in recent years to substitute the terms leukosis, myelosis and lymphadenosis for leukemia, myelogenous leukemia and lymphogenous leukemia, respectively. The reasons presented for the substitution of these newer terms for the older equivalents are that the newer terms are said to indicate more fundamental hematopoietic