New Yokk Agricultural Experiment Station. 73 



were prepared from each sample using the dilutions of 1 to 2 and 

 1 to 10. The plates were counted after five days at room temperature 

 and two days at 37°C. The udder, flank up to the hip joint and the 

 tail above the brush were then clipped on each of the cows, using a 

 power clipper. Between April 1 and May 9, 24 samples from each 

 cow were collected and tested as in the case of the preceding samples. 

 During this work care was exercised to carry on the barn operations 

 in as constant a manner as possible except that on each day two of 

 the cows were cleaned by hand and two by a vacuum cleaner as 

 explained on page 75. 



The results obtained from the samples collected under these con- 

 ditions are given in Tables XI and XII. 



It will be seen from Table XI that the average germ content of 

 the 88 samples of milk from the undipped cows was 204 per cc, 

 that the average of a like number of samples of the strippings was 

 71 per cc. leaving a balance of 133 germs per cc. to be accounted 

 for by the influence of the environment. 



In Table XII the average germ content of 96 samples of milk 

 from the same cows after they had been clipped was shown to be 

 320 per cc, the average from a like number of samples of strippings 

 being 112 and the balance to be otherwise accounted for was 208 

 per cc. 



An inspection of the results from the individual samples shows 

 that this difference is not due to excessive numbers in a single sample 

 as was the case in Table X but is the result of fairly constant differ- 

 ences between the two groups of samples. So far as these results 

 can be taken to indicate anything they indicate that clipping cows 

 increases the probabilities of germs finding their way into the milk 

 during the milking process. They certainly lend no support to the 

 prevailing idea that clipping the udder and flanks of cows is a valuable 

 aid in the production of sanitary milk. 



This outcome of the experiment was quite unforseen. However, 

 close observation of the cows suggested the following explanation. 

 Brushing or otherwise cleaning the normal coat of a cow removes 

 the loose dirt from the surface and the outer portion of the hair. 

 Dirt at the base of the hair is retained by the protecting coat. When 

 the hair is clipped the cleaning process removes perhaps a larger 

 proportion of the dirt, but during the succeeding milking process 



