The nutritional disturbances that occur during infancy are manifold, varying all the way from slight discomfort, vomiting, and other evidences of indigestion, to the severest intoxications, such as cholera infantum. With the advent of bacteriology it became evident that many of these disorders, especially those accompanied by fevers and intoxications, closely resembled the infections that were known to be due to bacteria. This view was further supported by the fact that nearly all of these conditions occur most readily when cow's milk is given, and are rare at the breast. The former teems with bacteria, "spoils, turns sour," etc., while the latter is practically sterile. It was easy to believe that the severer cases with fever and intoxication were due either to direct infection of the mucous membrane of the gastro-intestinal tract, or to bacterial activity with the formation of toxins in the milk, either without or within the body. The simpler, milder cases without fever and intoxication seemed easier to explain on the basis of purely food disturbances, irritation due to an excess, or too great concentration of one or the other food elements. The imperceptible shading of the mildest into the severest conditions made it hard to know where to draw the line between infection and food irritation. The absence of pathological lesions in the intestinal mucosa in so many of the severest intoxications made it evident that even here there was at least not an invasion of the intestinal wall itself by bacteria, as, for example, in dysentery, or ileo-colitis, where there is undoubtedly an infection of the mucous membrane, and where there is, moreover, a specific bacterium that causes it. The fact, furthermore, that intoxications yield almost immediately when all food is discontinued, and reappear when it is given again too quickly, while ileo-colitis is practically uninfluenced by this procedure, naturally raises the question whether in the former we have not a condition due to food alone, and in the latter one due to bacteria.

The present tendency is to attribute more importance to food itself as the disturbing factor in these disorders, and a decidedly less important role to bacteria, except, of course, in ileo-colitis. This change of attitude is mainly due to the epoch-marking work of two men, Czerny of Breslau, and Finkelstein of Berlin. In a series of papers on "Alimentare Intoxication"in the Jahrbuch fur Kinderheilkunde during the past two years, Finkelstein has demonstrated, it seems quite conclusively, that these intoxications, such as cholera infantum, and the prodromal stages, dyspepsia, etc., that lead up to them, are due purely to food - that is, to a disturbance in metabolism, and not to bacteria. They are thus related to such conditions as uremia and diabetic coma, rather than to ileo-colitis or typhoid. The work of Czerny has prepared us for accepting this view. In their great work on infant feeding Czerny and Keller have shown that the nutritional disturbances, due to the different food elements are due to metabolic conditions and are not simply indigestions nor infections. In the present discussion we will accept these conclusions, and will consider the diseases commonly classed as indigestions, or dyspepsias, entero-catarrh, or catarrhal enteritis, gastro-enteric intoxication (Holt), or alimentary intoxication, or summer complaint, or summer diarrhea and cholera infantum, as due to food itself - i. e., they are essentially digestive and metabolic disorders, and not due to infection of the mucosa, nor to action of bacteria upon food itself. Ileocolitis will be treated separately as essentially an infectious process.