Owing, in our opinion, to faulty classification and terminology of bacterial types, it is very common, especially on the Continent and, to a lesser extent, in U.S.A., to ascribe outbreaks of food poisoning to B. paratyphosus B, the common cause of paratyphoid fever. If such a conception is true, it is obvious that B. paratyphosus B can at one time cause paratyhpoid fever, at another an outbreak of food poisoning. Further, one would expect in outbreaks of either condition that some cases would be of the one clinical type while others would exhibit the other. In particular in outbreaks of paratyphoid fever in which the vehicle of infection was some form of food, it is to be anticipated, on this view, that a considerable proportion of the cases would be of acute food poisoning type.