This is a detailed report of the intestinal flora of seven puppies of one litter, four of which received natural nourishment and three were fed on modified cow's milk. The puppies fed on cow's milk soon showed a syndrome which closely resembled that of the "Milchnaehrschaden" of the artificially fed infants.
There was only a quantitative difference in the bacterial flora of the upper parts of the intestines. The artificially fed puppies showed more microorganisms in the smears of the intestinal content than those of the puppies fed on natural food. The older the puppies were, the more marked was the difference. Beyond the lower part of the ileum the difference in the flora was marked. In the puppies given natural food there was a preponderance of gram-positive bacilli, just as in naturally fed infants. In the intestinal content of the puppies fed on modified cow's milk, both gram-positive and