G34 



STATE BOARD OF AGRICULTURE. 



If the antibodies for Bad. abortus foimd in milk originate in the 

 blood stream it would seem reasonable to expect their presence in the 

 different quarters of tlie udder in about the same concentration. That 

 this is not the case is seen in the above table. Here we find that one 

 or more quarters may contain antibodies while the others are negative. 



The only way to account for this distribution of antibodies, it seems 

 to the writer, is to assume that there might be an invasion of one or 

 more quarters of the udder by Bad. abortus and a consequent local pro- 

 duction of antibodies. If this is found to be the case these tests might 

 prove to be of great value in studying the presence of Bact. abortus in 

 milk. 



As has been stated previously, tlie only means we now have of study- 

 ing the presence of Bad. abortus in milk are far from satisfactory in 

 that they are not delicate and require such an expenditure of time that 

 it is possible to study only a limited number of samples. By testing for 

 Bad. abortus antibodies, if these prove to indicate infected quarters of 

 a cow's udder, it would be possible to examine many samples of milk 

 where we now examine one. 



The agglutination test is simple and in blood serum tests gives ap- 

 proximately the same results as the complement fixation test. To deter- 

 mine whether or not the complement fixation test might be omitted a 

 comparison was made of the agglutination and complement fixation 

 reactions testing milk instead of blood serum. This is shown in Table 

 III. 



TABLE III.— A COMPARISON OF THE AGGLUTINATION AND COMPLEMENT FIXATION 

 REACTIONS FOR BACT. ABORTUS INFECTION TESTING MILK INSTEAD OF BLOOD 

 SERUM. 



In this table it is seen that the agglutination test reveals a higher 

 percentage of positive samples than does the complement fixation test 

 and is apparently more delicate. For these reasons the complement 

 fixation test is omitted in some of the following experiments. 



For the experiment given in Table IV, a cow was selected whose milk 

 had given a negative agglutination reaction since first tested, October 



