Although the specific causative agent of the rheumatic infection has not yet been demonstrated conclusively, the varied manifestations of the infection are now generally believed to be due to a micro-organism or to its toxin.
The conception of the rheumatic infection as being primarily a general infection, the extent and severity of the local manifestations depending on the intensity of the infection and the resistance of the child, is being more and more emphasized. In children, the rheumatic infection is characterized by periods of active infection followed by periods of quiescence, both being of uncertain duration, the infection involving indiscriminately, simultaneously and successively the heart, joints, skin and nervous system.
The determination of the onset, degree of activity, duration and quiescence of the rheumatic infection is of practical importance in diagnosis, prognosis and treatment.
The leukocyte count is taken as an index of infection in many diseases. Recently, Swift, Miller