Larson and Sedgwick3 observed that in complement fixation tests of the serums from women who had aborted, the percentage containing abortus antibodies was greater than that giving positive Wassermann reactions. In studying the blood serums of 425 children they found by the agglutinin absorption test, specific abortus agglutinins in 17%. They showed that children who had drunk milk from a herd where infectious abortion did not exist, did not harbor any of these agglutinins, Nicoll and Pratt,4 Cooledge,5 and others have shown that specific abortus agglutinins were present in the serum of persons who had drunk raw milk containing Brucella abortus, while Nicolle, Burnett and ConseilG have demonstrated their presence in the serum of men injected with this organism. Evans7 examined the blood serum of 500 patients suffering from various diseases and found that 59 contained specific agglutinins for Brucella abortus. Keefer8 reported the first case of Brucella abortus infection in America. The titer of the serum from this case was 1: 3,200. Evans 7 reported finding abortus agglutinins in three serums, one of which had a titer of 1: 160, while the other two had a titer ^ of 1:320. Duncan9 reported an abortus agglutinin titer of 1:2,400 with the serum of a patient suffering from undulant fever. Orpen,10 DeKorte,11 Ficai and Alessandrini12 and Viviani13 have reported similar cases which were undoubtedly due to Br. abortus. In these cases evidence pointed to infection from cattle. The blood serum from these patients had a fairly high titer.