Xew York Agricultural Experiment Station. 93 



either by L. A. Rogers or J. F. Nicholson.* The samples were 

 collected in sterile test tubes, at times with most elaborate 

 preparation of the animal, at others with no preparation aside from 

 the ordinary grooming. The results did not indicate that these 

 variations in the preparation of the animal affected the germ 

 content of the samples. 



Plates were made promptly on agar or gelatin and at times on 

 both. The gelatin plates were ordinarily counted at the end of five 

 days at room temperature, the agar plates after three days at 

 37 °C. Owing to the undeveloped state of bacteriological classifi- 

 cation at that time only quantitative results were obtained. "While 

 these observations were merely preliminary they were of some 

 value in establishing the range of bacterial content which may be 

 expected in practice. 



During 1907-11 one of us (W) collected and studied 766 

 samples from 20 cows in the Station herd. Only quantitative re- 

 sults were obtained from approximately the first 50 of these 

 samples but the remainder were studied both quantitatively and 

 qualitatively. Owing to the lapse of time since the study of 

 1900-02, the herd had entirely changed. The destruction of the 

 Station barns bv fire in 1904 had further changed conditions so 

 that these two sets of observations of the Station herds have the 

 same relative value as would the study of two separate herds. 



This somewhat extended study of conditions in these two herds 

 was supplemented by a study of a sample from each quarter of the 

 udder of 46 cows belonging to Mr. A. G. Lewis or a total of 184 

 samples from this herd. 



Accordingly, the present publication is a discussion of the 

 quantitative relationships of 1,274 samples representing 83 cows 

 and of the qualitative findings from 900 samples representing 63 

 cows. 



* Mr. Rogers is now head of the research laboratory of the Dairy Division 

 of the Bureau of Animal Industry, U. S. Department of Agriculture, and 

 Prof. Nicholson, head of the Bacteriological Department of the University of 

 Idaho. When the above work was done they were Assistant Bacteriologists 

 at this Station. 



