The importance of diarrheal diseases in children as an outstanding cause of death is well recognized. Prior to the present widespread pasteurization of milk, more than 50 per cent of the infant mortality during the summer months was due to diarrheal diseases; even since the general improvement in the milk supply, brought about especially by pasteurization, these diseases constitute a large proportion of the causes of deaths in children during the hot season.
The term "diarrhea" is used to include all conditions attended by frequent loose stools. Types of diarrhea may be classified under two heads: those of known etiology and those of unestablished etiology. In the first group are included (a) bacillary dysentery1 (b) amebic dysentery2 and (c) paratyphoid fever;3 in the second group are placed all other types of conditions characterized by loose bowel movements. There are more or less well recognized clinical classifications; for