This paper is an attempt to answer the question: Is infection of the mastoid the cause of acute intestinal intoxication in infants? During the past five years this question has been intensively studied by pediatricians and otologists in Canada and the United States. The literature has been ably reviewed by G. M. Coates.1The students of this problem are at present roughly divided into two widely divergent camps: those who believe that infection of the mastoid is the cause of acute intestinal intoxication in infants and those who believe that it is not. Physicians and surgeons of eminence are to be found in each camp, but the majority of their papers support, to some extent, the idea that infection of the mastoid antrum may be the cause of this mysterious disease. THE DISEASE An intense form of gastro-intestinal disease affecting infants under 2 years of age, occurring apparently in