ROBERT S. BREED 379 



Later, Moore and Ward/ following up a suggestion previously made by Moore, 

 cultured excised pieces of udder tissue and found that bacteria were present even in 

 the secretory portion of the gland. Bolley,- and Moore and Ward, as well as later in- 

 vestigators, have found that certain species of bacteria become localized in particular 

 quarters of the udder, and that they are able to persist in this habitat for months or 

 years. 



TYPES OF BACTERIA FOUNT) IN THE UDDER 



Even in 1875-78 Lister^ found that the milk drawn with aseptic precautions 

 might contain micrococci which produced an orange pigment. Others likewise found 

 micrococci abundant in freshly drawn milk until in 1913 Harding and Wilson'' re- 

 ported after an extensive investigation: "No organisms producing spores and no mo- 

 tile forms were found. Seventy-five per cent of the forms were micrococci, but only 

 two streptococci were found." Ninety-six per cent of all the types found, whether 

 micrococci or non-spore-forming rods, were gram positive. None of the organisms 

 fermented sugars with the formation of visible gas in fermentation tubes. 



Their work and that of later investigators has established the fact that common 

 types of micrococci occurring in normal udders are identical with the classic types 

 known to students of human bacteriology as Micrococcus albus, M. aureus, and M. 

 citreus, and they are so classified by Evans and by Hucker.s Not all of the udder mi- 

 crococci belong to these species, however. 



ACID-PROTEOLYTIC UDDER COCCI 



Certain types of micrococci and streptococci are found that are both acid and 

 proteolytic in their action on milk. Gorini was the first to recognize these organisms, 

 and he soon came to feel that they play an important role in ripening hard rennet 

 cheeses of the Grana, Emmenthal, Edam, and Cheddar types. While Gorini*' found 

 some of these to be gelatin liquefiers {Micrococcus casei acido-proteolyticus I), he also 

 found some that do not liquefy gelatin (M. casei acido-proteolyticus II). Freuden- 

 reich^ early in his work found one of these types that was lemon yellow and named it 

 Micrococcus casei amari, as it produced bitter cheese. Bitter cheese was obtained also 

 by Hucker and Marquardt^ when they used cultures of acid-proteolytic cocci. 



Burri and Hohl' recognize that some of these cocci are very similar to the ordinary 

 streptococcus of sour milk (Streptococcus lactis) except that they liquefy gelatin. They 



'■ Moore, V. A., and Ward, A. R.: Cornell Agric. Exper. Sta. {Ithaca) Bull. 178. 1900. 



^Bolley, H. L.: Centralbl.f. Bakteriol., Abt. II, 1, 795. 1895. 



3 Lister, J.: Tr. Roy. Sac, Edinburgh, 27, 319. 1875. 



'•Harding, H. A., and Wilson, J. K.: New York Agric. E.vper. Sta. (Geneva) Tech. Bull. 27. 1913. 



s Evans, A. C: 3 . Infect. Dis., 18, 437. 1916; Hucker, G. J.: NewYork Agric. Exper. Sta. {Ge- 

 neva) Tech. Bulls, gg-ioj. 1923. 



^ Gorini, C: Le Lait, 7, 36. 1927. (A review with bibliography.) 



'von Freudenreich, E.: Landw. Jahrb. d. Schweiz, 8, 136. 1894. 



* Hucker, G. J., and Marquardt, J. C.: New York Agric. Exper. Sta. (Geneva), Tech. Bull. 117. 

 1926. 



'Burri, R., and Hohl, J.: Landw. Jahrb. d. Schweiz, 31, 315. 1917. 



