The majority of students to-day place responsibility for gastroenteritis upon the bacteria known to be present in the various intestinal tracts, mentioning especially colon and proteus groups, streptococci, the necrosis bacillus and anaerobes of the Welch class. In a few of our studies of intestinal bacteria in cases of enteritis one thing has been very definite and that is that in the intestinal content of animals whose food is largely meat, Gram-negative bacilli have predominated, whereas in herbivorous animals Gram-positive organisms have been most numerous. From the observations of Kitt, Strassberger and some others, the normal flora of domesticated animals is subject to wide variations so that our observations must receive confirmation before they are finally acceptable. We have on several occasions isolated from carnivorous intestines Bact. paracoli, Bact. suipestifer and other members of this group. We have no reliable cultural data upon the herbivorous intestine and can only quote the Gram pictures as mentioned above. On two occasions, an eland and an elk, a very large number of forms corresponding to necrosis bacillus were seen; to this organism Kitt gives considerable power in the production of necrotizing processes. TABLE 11. _This table shows an analysis of all cases of gastroenterocolitis. The left half of the table is an analysis of orders upon which one hundred or more autopsies have been done, the right half of orders with fewer than that number. The left half is expressed in percentages, the right half in number of cases only since percentages might be misleading. Left hand table: First column is percentage of gastroenterocolitis per order; next five columns the percentages in which each of the factors in the headings was believed responsible; the last three columns show the participation of each of the divisions of the intestinal tract; thus Primates had all told 24.8 per cent. of inflammations of which 7.2 per cent. were in stomach, 18.3 per cent. in the intestines and 8 per cent. in the colon; obviously many had all three sections affected. Right hand table is constructed on a similar basis except that number of cases is quoted, not percentages, and the total is put in the last column._