Since the disease agranulocytosis, or acute granulopenia, was first described in Germany1in 1922 and in the United States2in 1924 there has been much study concerning its pathogenicity and, in particular, its etiology. Since it was first described thirteen years ago there have been hundreds of reports of the disease in the medical literature and it was responsible for more than 1,500 deaths in the United States alone in the three year period ended in 1934. There has been considerable discussion as to the occurrence of the disease before 1922, and this question is important because of the possible relation to various etiologic factors. It seems obvious that this disease is one that presents little diagnostic difficulty, since the clinical picture is dramatic, the outcome is usually fatal, and the physician who makes leukocyte counts should