by positive reactions to the complement fixation and agglutination tests. His results indicate, he believes, “that the bull is not so important a factor in transmitting abortion as many believe.” The conclusions are: “Bulls may become infected with abortion bacilli. Bulls that reacted to the blood tests were incapable of disseminating the abortion disease to the abortion-free heifers with which they were mated. Bulls appear to possess a sexual or individual immunity to abortion infection that renders them less susceptible than cows and induces a milder form of the disease. The resistance appears to be due to certain anatomic and physiologic differences in their sexual organs which make them less favorable places for the growth of the abortion germs than those of the opposite sex.” Buck, Creech, and Ladson (6) applied the agglutination test to 325 mature bulls, of which 288 were negative and 37 positive. _Bacillus abortus_ was isolated from five animals, of which three showed marked lesions, two in the seminal vesicles, and one in the left testicle. They conclude: “_B. abortus_ may involve organs of the generative apparatus of bulls, producing chronic inflammatory changes. Of the generative organs, the seminal vesicles appear to furnish the most favorable site for the lodgement and propagation of abortion infection.” Schroeder and Cotton (7) cite the case of a bull which reacted to the abortion test and, on post mortem, _Bact. abortum_ was isolated from an abscess of one epididymis. They state: “Our attempts to produce a similar case of infection artificially failed, and, in agreement with the difficulties many investigators have had to obtain incriminating evidence against bulls, we have thus far failed to infect bulls in any way that justifies the assumption that they are important factors in the dissemination of abortion disease.” Further, they conclude: “Regarding the dissemination of abortion disease by bulls, we may say, however, that it would be foolhardy in the dim light of our present knowledge to take liberties with reacting bulls, or bulls from infected herds, or promiscuously used bulls.”