New Yoke Agrictjltukal Experiment Station. 91 



The work of Schulz was confirmed by Moore, 4 who concluded 

 that " Freshly drawn fore milk contains a variable number of bac- 

 teria, varying in number from a few individuals to many thou- 

 sand per cubic centimeter. These are distributed among several 

 species. The last milk drawn at a regular milking contains, as 

 compared with the fore milk, very few micro-organisms. It is the 

 exception, however, to find a sample of milk that is free from mi- 

 cro-organisms unless it is taken during the latter part of the milk- 

 ing process from a single quarter of the udder." 



As the result of these and similar observations it was held that 

 bacteria might find their way into the teat opening and multiply 

 to some extent in the milk cistern, but that they were washed out 

 more or less completely during the milking process. 



In his earlier paper Moore suggested the desirability of direct 

 examinations of excised tissue from functioning udders of freshly 

 slaughtered milch cows as a means of settling the question of the 

 bacterial invasion of the upper portions of udders. He later 5 re- 

 ported the results of such examinations and this work was extended 

 by one of his students, Ward. These direct examinations showed 

 that bacteria were uniformly present in the finer subdivisions of 

 the udder. The work of Bolley 7 had indicated that certain species 

 were able to persist in an udder for considerable periods and 

 Moore and Ward 8 studied an instance where this udder contamina- 

 tion was of considerable economic importance. 



Later work has confirmed the conclusion of Moore and Ward 

 that bacteria are practically always present in the udders of 

 healthy cows but it has also shown that the numbers of bacteria 



4 Moore, V. A. Preliminary investigations concerning the Mumber and 

 nature of bacteria in freshly drawn milk. U. S. Dept. Agr. An. Ind. An. Rpt. 

 12 & 13:261-266. 1897. 



s Moore, V. A. The normal bacterial invasion of the cow's udder. Proc. 

 Soc. Prom. Agr. Sci. 1899:110-113. 



e Ward, A. R. The persistence of bacteria in the milk ducts of the cow's 

 udder. Jour. A.pp. Micros. 1:205-209. 1898; also The invasion of the udder 

 by bacteria. X. Y. (Cornell) Agr. Exp. Sta. Bui. 178. 1900. 



7 Bolley, H. L. Ueber die Konstanz von Bakterienarten in normaler Roh- 

 (fore) Milch. Cent. Bak. II Abt. 1:795-799. 1895. 



s Moore, V. A., and Ward, A. R. An inquiry concerning the source of gas 

 and taint producing bacteria in cheese curd. N". Y. (Cornell) Agr. Exp. Sta. 

 Bui. 158. 1S39-. 



