Since Filatow's1 first allusion in 1885 to an idiopathic lymph adenopathy there have been more than 110 articles published on glandular fever, and about half as many articles on similar or identical conditions variously named. In the eighteen nineties numerous small epidemics were reported in England, on the Continent, and in this country. In 1907 Turk2 reported blood observations in cases with lymphadenopathy, and since 1920 there has been a generalized feeling that mononucleosis is a constant feature of glandular fever. Even now, forty-one years after the first recorded observations on the disease, there is considerable confusion, and some able clinicians are inclined to disregard the whole group of cases rather than draw definite conclusions as to the existence of a true disease entity among them. Until recently most important textbooks and systems of medicine contained at most only brief mention of the condition. The clinical features of glandular fever,