First definite description of leukemia as a blood disorder; a case under the care of Sir R. Christison but reported by Bennett. On p. 400 of the same journal is a report of a case by D. Craigie, referring to a patient seen in 1841 but not recognized as leukemia until Craigie heard of Bennett’s case in the same hospital. Bennett published a monograph on leucocythemia in 1852, in which he included the first illustrations of the microscopic appearance of the blood in leukemia.