NIAZI and State1 reported that the serum level of a substance which reacts with diphenylamine was elevated in several disease states, including rheumatic fever. Likewise, when a patient's serum was heated with Dische's diphenylamine reagent Ayala and his associates2 observed an association between the intensity of the purple reaction and the degree of rheumatic activity. The present report includes a study of the diphenylamine values in three groups of children with carefully observed rheumatic fever. One group was treated in a uniform manner during the acute illness; a second group received several types of therapy following admission to the hospital; another was a group of children with quiescent rheumatic fever, who were attending school and receiving no treatment.
Technique for Determining Serum Diphenylamine Values.
—The semimicro procedure described by Ayala, Moore, and Hess has been employed throughout this study.3 In this procedure, 5 ml. of 5%