EXPERIMENT STATION REPORTS. 171 



REPORT OF RESEARCH ASSOCIATE R. L. TWEED 



Under Adams la I have continued the following phases of the project as 

 related to infectious abortion. 



1. Studies upon the significance of high cellular count of milk from Bac- 

 terium abortus infected udders as compared with that from non-infected 

 udders. 



2. A study of the teats as an avenue of Bad. abortus infection of the udder. 



3. Feeding experiments with Bad. abortus infected milk. 



4. Efforts to devise better methods for studying the presence of Bad. 

 abortus in the udder. 



5. Bacteriological and pathological studies of Bad. abortus infections of the 

 udder. 



Under the last phase of this project Graduate Assistant Otto H. Friede- 

 mann this year submits a thesis for the master's degree, "A study of the 

 nature of Bad. abortus infection of the udder." 



My work in relation to fermentation has been as follows: 



Vinegar: From July 1, 1921, to June 30, 1922, 130 requests for vinegar 

 cultures were received, 116 yeast cultures were sent out and 90 cultures of 

 acetic bacteria not including two gallons of culture sent to a Michigan vine- 

 gar company for starting generators, and 40 lots of chemicals for making 

 honey vinegar. Fifty-four of the requests for vinegar cultures were from 

 outside the State. 



The decrease in requests for vinegar cultures during the past year was 

 probably due to the shortage of apples last fall. 



Seventy-six samples of vinegar were tested, the analysis of which are 

 tabulated herewith: 



