As a starting point I will refer to a document with which I am sure you are all familiar-the Report [17] of the Child Life Committee of the Medical Research Council on "Social Conditions and Acute Rheumatism," which appeared in January 1927. This well-controlled and thorough investigation was the combined work of three teams of observers at St. Tbomas's Hospital, the Hospital for Sick Children, Great Ormond Street, and the Royal Hospital for Sick Children, Glasgow. The medical and social histories of 721 rheumatic families, 200 control families and 2,000 school children living in Poor Law schools, were ascertained. The possible medical factors investigated included familial incidence and heredity, the familial incidence of sore throat and throat conditions (especially tonsillectomy).The possible social factors investigated included maternal care, exposure, sleeping accommodation, clothing, cleanliness and distance from school, condition, birthplace, occupation and income of the parents, housing conditions, and the sites of houses. Yet of all this thorough and patient work "the findings are largely negative." To quote Dr. Still's own words: " The comparison between the social conditions under which the rheumatic and control children were living has failed to reveal any differences or any factor in the social circumstances of the rheumatic children which might be described as causative . . . The maternal care was found to be inferior, the amount of subjection to exposure appeared to be greater, and the clothing less good in the case of the rheumatic children. The health of the parents was also not so good in the rheumatic as in the control families. In the St. Thomas's Hospital data a higher proportion of rheumatic than control families were found in houses situated under 50 ft. above sea-level."The evidence as to whether a "rheumatic type " of child could be distinguished in relation to the pigmentation of hair and eyes was also so conflicting as to be practically insignificant.Perhaps the most important positive finding was the low incidence found in the children living in the Poor-Law residential schools, discounted though it was to some very slight degree by the fact that a child with recognized heart disease or chorea would not presumably be sent to these schools. Nevertheless, the fact that only 1% of these children were affected suggests that children living under the better general hygiene of such institutions are much less frequently attacked than children of the same class living under the ordinary conditions of a poor home.The most important factor not dealt with in the Committee's Report was diet, whilst urbanization was another factor which could not be assessed by the Committee, for their investigations were made in London and Glasgow. The importance of this well-known factor, and especially the high incidence in the city of Bristol, were the chief lessons of the report [2A] of the Bristol and three Counties investigation into rheumatic heart disease, the investigation inspired by the late Dr. Carey C...