EXPERIMENT STATION BULLETINS. 643 



Moliler and Traum, in studying the pathogenicity of this organism to 

 man, examined the sera from forty-two human beings by complement 

 fixation and agglutination tests, using Bad. abortus as antigen. No 

 positive results were obtained by these tests. The authors say: "Out 

 of fifty-six tonsils and adenoids inoculated into guinea pigs, tonsil No. 

 3 produced nodular areas in the liver, but cultures from this organ re- 

 main sterile. Tonsils from case No 8, inoculated into two guinea pigs, 

 showed in one of them after three months distinct lesions of infection in 

 the liver, spleen, and testicles, and B. abortus was obtained from the 

 lesions." 



Larsen and Sedgwick have made an extended study of human infec- 

 tion by this organism. They state : "If the B. abortus is pathogenic for 

 human beings, as it is for guinea pigs, and can be transmitted through 

 the digestive tract, as is the case with cattle, we would expect infants 

 and children to be the subjects most frequently infected. We have to 

 date examined the blood of four hundred and twenty-five children by the 

 complement fixation methods, and have found at least some support of 

 the above expressed hypothesis. Of these four hundred and twenty-five 

 cases we found seventy-three positive and three hundred and fifty-two 

 negative reactions. In other words, the blood of seventeen per cent con- 

 tained antibodies against B. ahortusJ' The same authors in an attempt 

 to answer the question : "Are these antibodies in the blood of children 

 the result of an active or passive immunity?" examined a number of 

 samples of milk from cows that had recently aborted, without being 

 able to demonstrate the presence of Bad. abortus antibodies. 



In their later investigations Sedgwick and Larsen found that new- 

 born children who had not received cows' milk gave negative blood re- 

 actions in all of forty-two cases tested. One infant, taken from the breast 

 on the seventh day after birth and fed on cows' milk, gave a positive re- 

 ation on the twenty-first day. Positive reaction was obtained in tAvo 

 children with enlarged spleens; children with many common diseases 

 of childhood, including rickets, gave negative reactions. 



Nicholl and Pratt also obtained positive agglutination reactions with 

 the blood sera of some children. In regard to their significance they 

 say: 



"The presence of serum reactions is suggestive, but they again are not 

 conclusive, failing the isolation of the bacillus from the lesions. That 

 the ingestion of bacilli in large doses may be followed by the presence 

 of antibodies in the blood, has been demonstrated by several investiga- 

 tions. ..." 



Kamsey examined the blood of one hundred and sixteen children, of 

 whom fifty-eight were boys and fifty-eight were girls. Of these, seven 

 cases gave a positive complement fixation reaction — six boys and one 

 girl. 



That this reaction of the blood of children may indicate a passive im- 

 munity due to the ingestion of milk containing the antibodies is sug- 

 gested by the work of Ehrlich and Wassermann, who found that young 

 mice are capable of assimilating antitoxin through the intestinal canal 

 and of storing it in the blood, thus acquiring a certain degree of passive 

 immunity. 



The author has shown in another part of this paper that Bad. abortus 

 antibodies are often present in milk as it comes from the udder of an 



