In Detroit the most severe and rapidly fatal forms of infantile diarrhea begin to make their appearance about the third week of August, reach a peak during September and become less frequent in early October. This curve corresponds closely to that observed in other cities having approximately the same climatic conditions. Despite the unusual and excessive heat of the early summer of 1930, comparatively few patients with diarrhea were admitted to the Children's Hospital until the last week of August; hence our studies have all been made over a rather brief period of about five weeks.
During the time that we have been conducting our observations, there have been admitted to our ward patients suffering from diarrheas of all degrees of severity and of various etiology. We have experienced considerable difficulty in classification, because often it was practically impossible to make a definite statement as to the cause which, in