(6) Spoiled food is obviously a very prime factor in inflammations of the gastrointestinal tract. Its operations are illy understood except perhaps when products of fermentation or putrefaction prevent digestive action or are absorbed. If in small quantities not sufficient to cause acute fermentative inflammation or intoxication, such substances frequently taken may doubtless produce chronic catarrhs. Many animals are fed upon vegetable mashes, or stews which can decompose, while bad meat may occasionally be fed. We had a rather serious outbreak of enteritis in small Carnivora from the use of fowl heads obtained at hotels; some of these cases were shown to be due to B. paracoli, thus to be looked upon as infections. Dirty food while not spoiled may carry with it organisms of decomposition, or of infective qualities, or the dirt may act as an irritative foreign body. We have found that for delicate ungulates (antelopes) it is highly desirable to screen grain, and that the grade of hay should be of the best. (7) Infectious conditions are of great importance under certain circumstances but with the exception of hog and fowl cholera, the dysenteries and a few other diseases, do not as a rule play a great part in mortality as specific diseases unless of course an epizoötic appear. The greater problem is to understand bacterial action in the face of other factors. Are infectious germs introduced with food and drink in every case of gastroenteritis or do some other factors activate those already present in the gut tract? Unfortunately these questions cannot be answered directly. We can, however, point out which groups of bacteria are most common in some of the orders, which orders are most susceptible to bacterial invasion and which to local lesions with intoxication. The greatest problem in the field is the interrelation of germs of various sorts in the intestinal tract. Certain varieties are known to develop intoxicating aromatic substances, others to elaborate or excrete fatty acids, still others to form antiferments but the conditions existing in the various kinds of intestinal tracts are too little understood to help very much in this study.