BACILLUS CO LI COM MUNIS. 395 The bacterium coli seems to be the pathogenic agent of the greater number of summer infantile diarrheas. This organism is the more often associated with the streptococcus pyogenes. The virulence, more considerable than in the intestine of a healthy child, is almost always in direct relation to the condition of the child at the time the culture is taken, and does not appear to be proportional to the ulterior gravity of the' case. The mobility of the Bacterium coli is in general pro- portional to its virulence. The jumping movement, nevertheless, does not correspond to an exalted virulence in comparison with the cases in which the mobility was very considerable, without presenting these jumping movements. The virulence of the Bacterium coli found in the blood and other organs is identical with that of the Bac- terium coli taken from the intestine of the same indi- vidual. Lesage,1 in studying the enteritis of infants, found that in 40 out of 50 cases depending upon the Bacillus coli the blood of the patient agglutinated the cultures ob- tained, not only from his own stools, but from those of all the other cases. From this uniformity of action Le- sage very properly suggests that the colon bacilli in these cases are all of the same species. The agglutinating reaction occurs only in the early stages and acute forms of the disease. It is not difficult to immunize an animal against the colon bacillus. Loffler and Abel immunized dogs by progressively increased subcutaneous dosage of live bac- teria, grown in solid culture and distributed through water. The injections at first produced hard swellings. The blood of the immunized animals possessed an active bactericidal influence upon the colon bacteria. It was not in the correct sense antitoxic. In intestinal diseases, such as typhoid, cholera, and 1 Semaine Medicate, Oct. 20, 1897.