In a previous paper1 I discussed the various theories which have been proposed to explain the great prevalence of gastro-enteric diseases in infants during the summer. The general conclusion in that study was that the heat theory is inadequate to explain the occurrence of diarrhea during the hot weather, although it may act as a predisposing cause. Excessively hot weather also increases the mortality of infants suffering from digestive disorders.
Three years ago the study was taken up again. The cases were studied from the practitioner's standpoint. Each case was studied carefully in regard to its history and clinical characters. The question at issue was, what kind of cases make up the class which bring about the great mortality of the summer?
First, there is the infant who has been suffering for a long period from digestive disorders, has lingered at the threshold of death, and the sudden appearance