Sir Leonard Parsons and the scientific basis of paediatric haematology.

When considered as a subspeciality of paediatrics and a sine qua non of the modern academic environment, paediatric haematology is a relative latecomer. This is not surprising as diseases of the blood were for a long time considered as a minor problem when compared with the great challenges of infectious and nutritional disorders that faced the early pioneers of paediatrics. The early history of paediatric haematology is too closely interwoven with general haematology for it to be traced separately. However, the early discoveries of the pioneers of haematology (Ehrlich, Metchnikoff, Landsteiner, Minot, Castle and Whipple to mention just a few) were applied to the special problems of childhood and infancy by investigators who, with few exceptions, were paediatricians with ranging interests rather than haematologists with a specialized background. This is true even for those whose names have become immortalized through eponyms, such as Cooley, Diamond, Blackfan and Fanconi. One name that has not been immortalized is that of Heinrich Lehndorff who devoted his life to the study of normal and abnormal haematological conditions in childhood and who published between 1906 (when 27 years old) and 1963. Lehndorff was forced to leave Austria in 1939 and found temporary shelter with the subject of this article, Leonard Parsons, before moving to the USA (Zuelzer, 1998). Lehndorff was only one of many who was attracted to the wisdom and mentoring of Leonard Parsons, who is often regarded as the Grand Old Man of British Paediatric Haematology. Parsons was an original thinker who refused to accept the confused semantics of childhood anaemias and created his own system along pathophysiological lines.