As one descends the zoological scale the first gastrointestinal tract prepared for the nutritional care of bulky food is to be found in the RODENTIA. This order presents a great variety of shapes and arrangements of the stomach, but the outstanding feature, with very few exceptions (cf. spermophiles), is the development of the cardiac and fundal divisions ostensibly for the reception of a large bulk of coarse food to be digested at leisure. Some genera like the hamster (_Cricetus_) have a stomach closely resembling the ruminants, while that of the spermophile suggests the equine stomach. The pyloric end, variable in many ways, greatly resembles the abomasum. So too the duodenum is large, loose and distensible while the copious small gut ends in a very large cecum, shaped at times in a manner which has led to the term “colonic stomach.” The colon is variable and not always supplied with longitudinal bands and sacculations. In regard to incidence of gastrointestinal disease, rodents occupy a middle position in the table. The stomach seems a vulnerable section of the tract. Dilatation of the left hand section is common, due, to all appearances, to fermentative processes which have as a result the softening of the mucosa so that even immediately after death it will separate almost entirely. In these cases the pyloric part need not participate but may remain flat, smooth, soft and pink. This condition is slightly more common in the compound than in the simple stomachs. In some of this order, especially rats and cavies, there is a fermentative gastroenteritis expressed by injection and edema of the pylorus and duodenum, and much frothy mucus. It was at first thought that some relation might exist between this condition and the absence of the gall- bladder, but it occurs in varieties possessing this structure. The reaction of the intestine to irritation in this order is peculiar in two ways, the occurrence of mucus and the activity of the lymphatics. In all the inflammations from and including the stomach to the cecum, mucus is conspicuous. At times it is thin or loose and mixed with contents, while at others it forms a relatively close covering for the mucosa almost like a false membrane. Rodentia are peculiar in the promptness and clearness with which the follicles of the intestinal wall and mesentery enlarge in inflammation. They appear as pale, well outlined or diffuse opacities in the wall or as distinct plaques prominent on the surface. The PROBOSCIDEA are represented by one Elephant (_Elephas indicus_), in which a mild catarrhal change was seen in the middle stretches of the small intestine. This was of little importance as a cause of death, there being several other diagnoses, and was probably a terminal affair.