ISTew York Agricultural Experiment Station. 119 



Euth S. gave no milk from the left front quarter of her 

 udder. 



It will be noted that in one or more quarters of many of the 

 cows a single organism persisted for long periods and during this 

 time it was the predominating organism in most cases. These 

 observations ofTer the strongest evidence for the inference that 

 such forms have so adapted themselves to the conditions found in 

 the interior of the udder as to be considered fairly permanent in- 

 habitants. Such being the case it is hard to understand why they 

 do not attain much larger numbers than have been observed dur- 

 ing these studies. 



It will also be observed that in those cases where a given form 

 is abundant in one quarter it is at least occasionally met in the 

 milk from the other quarters. This may be explained on the basis 

 that it was really present all of the time but was missed in the 

 cultures. While this may have been the case in some instances, 

 the use of one cubic centimeter sample of milk at each examina- 

 tion should have reduced this difficulty very markedly since an 

 organism which is present in a proportion of less than one or- 

 ganism to a cubic centimeter of milk is surely not very abundant. 

 On the other hand, the spreading of the germs from one quarter 

 to another may have been connected with the ordinary milking 

 process. While it is the aim of most milkers to avoid wetting 

 the hand, they are frequently moistened, especially in the act of 

 stripping. With hands thus moistened the infection of the ex- 

 terior of one teat with the germs from the other quarter is rela- 

 tively easy. 



The yeast culture was so abundant and so constant in the left 

 back quarter of Millie G. as to put at rest any doubt as to its 

 being a member of the udder flora. 



While the persistence of a given group in a single udder, as 

 well as its distribution among the various quarters of an udder, 

 is well shown in Table X, the distribution of the various groups 

 among these fifteen cows is better shown in Table XI, 



