630 STATE BOARD OF AGRICULTURE. 



of the udders. During the whole of the period covered by the experiment 

 there was no visible alteration either in the udders or in the milk. 



A second series of experiments was made in which two goats were in- 

 oculated subcutaneously with 10 c.c. of an emulsion of the bacillus in 

 salt solution, and a third intravenously with the same quantity of an 

 emulsion or about half the density. 



The abortion bacillus was excreted in the milk of 2 of the goats (one 

 infected subcutaneously and one intravenously) 24 hours after injection. 

 The excretion of bacilli had not ceased 8 weeks after the commencement 

 of the experiments. In the other goat inoculated subcutaneously the 

 bacillus was not found in the milk 24 hours after inoculation, and it was 

 found onlv on the 4 following davs. 



Cotton concludes from his investigations that : "1. The bacillus of 

 infectious abortion may and in most cases does persist in the udders of 

 cows that have aborted, for years and possibly for the balance of their 

 lives; and during this time is eliminated more or less continuously with 

 their milk." 



"2. It may make its appearance in the milk months before abortion 

 occurs, even before a conception that is terminated by an abortion." 



"3, It may be eliminated for years from the udders of cows that 

 have never aborted." 



The investigators mentioned in the foregoing review have shown that 

 Bad. ahortiis is often present in milk as it comes from the udders of 

 apparently healthy cows. If this is accepted as true it is easy to see 

 that the infection might be spread to young calves through the medium 

 of the milk. The possibility of human infection must also be considered. 



It now remains to develop more delicate and rapid methods for de- 

 tecting the presence of this organism in milk, in order that a greater 

 number of samples may be examined, and that conclusions as to the 

 significance of the presence of this bacterium in milk may be more rapidly 

 obtained. 



With these objects in view our investigations were directed along the 

 following lines: 



Part I. Methods of studying the presence of Bad. ahortus in milk. 



Part II. A study of the effect of Bad. abortus upon man. 



Part III. Facts disclosed by a study of the presence of Bad. abortus 

 in milk by means of the Agglutination Test. 



Part I. 



Methods of Studying the Presence of Baderium abortus (Bang) in Milk. 



As mentioned in the introduction to this paper the isolation of Bad. 

 abortus from infected material is very difficult owing to the fact that 

 this organism when first isolated is neither aerobic nor anaerobic but 

 requires an atmosphere for growth which is partially depleted of oxygen. 

 This proper oxygen pressure has been obtained by investigators in 

 several ways. Briefly these are as follows: 



In the cultural method devised by Nowak, the proper oxygen tension is 

 obtained by growing agar streaks of the suspected material in a closed 

 jar with Badllus subtilis, having one sq. cm. of culture surface for each 

 15 c.c. of jar capacity. The small colonies usually will have appeared 



