The bacillus discovered by Gärtner (_loc. cit._) and known as _B. enteritidis_ or Gärtner's bacillus is commonly taken as the type of one of the agglutinative varieties. Bacilli with all the characters of Gärtner's bacillus have been found in meat poisoning epidemics in various places in Belgium and Germany. Mayer[69] has compiled a list of forty-eight food poisoning outbreaks occurring between 1888 and 1911 and attributed to _B. enteritidis_ Gärtner. These outbreaks comprised approximately two thousand cases and twenty deaths. In twenty-three of the forty-eight outbreaks the meat was derived from animals known to be ill at the time, or shortly before, they were slaughtered. Sausage and chopped meat of undetermined origin were responsible for eleven of the remaining twenty-five outbreaks. Two of the _B. enteritidis_ outbreaks were attributed to _Vanille Pudding_; one, to potato salad. In other food poisoning outbreaks a bacillus is found which is culturally similar to the Gärtner bacillus, but refuses to agglutinate with the Gärtner bacillus serum. Its cultural and agglutination reactions are almost, if not quite, identical with those of the bacilli found in human cases of paratyphoid fever which have no known connection with food poisoning. Mayer[70] gives a list of seventy-seven outbreaks of food poisoning (1893-1911) in which organisms variously designated as "_B. paratyphosus_ B" or as "_B. suipestifer_" were held to be responsible. The total number of cases (two thousand) and deaths (twenty) is about the same as ascribed to _B. enteritidis_. According to Mayer's tabulation meat from animals definitely known to be ailing is less commonly implicated in this type (ten in seventy-seven) than in _B. enteritidis_ outbreaks (twenty-three in forty-eight). Sausage and chopped meat of unknown origin, however, were connected with eighteen outbreaks. The bacillus named _B. suipestifer_ was formerly believed to be the cause of hog cholera, but it is now thought to be merely a secondary invader in this disease; it is identical with the bacillus called _B. paratyphosus_ B in its cultural and to a large extent in its agglutinative behavior, but is regarded by some investigators as separable from the latter on the basis of particularly delicate discriminatory tests. Bainbridge, Savage, and other English investigators consider indeed that the true food poisoning cases should be ascribed to _B. suipestifer_ and would restrict the term _B. paratyphosus_ to those bacteria causing "an illness clinically indistinguishable from typhoid fever." German investigators, on the other hand, regard _B. suipestifer_ and _B. paratyphosus_ B as identical. My own investigations[71] indicate that there is a real distinction between these two types.