276 MILK 



abortus in 23.4 per cent, of the samples, the highest number being 

 50,000 per cubic centimeter. 



Probably many reports of finding streptococci or Streptococcus 

 pyogenes in milk from apparently healthy udders in reality mean 

 the presence of Streptococcus lacticus (Bacterium lactis acidi). 



In the milk of a cow examined by Hastings and Hoffmann 

 90 per cent, or over of the total germ content consisted of a strep- 

 tococcus very similar to Streptococcus pyogenes in morphology 

 and in its biochemical reactions. Since no udder disease could 

 be observed, it is probable that this also was Streptococcus lacticus. 



Streptococci have been known to occur in market milk quite 

 frequently. There are many reports of such findings in the 

 literature, but there is no evidence in the majority of these re- 

 ports that the streptococci were derived from the udder, and they 

 may have been external contaminations. 



Bacilli of the Bacillus coli group were isolated from milk 

 obtained directly from the udder by v. Freudenreich, although 

 not frequently. He also found an organism similar to Bacillus 

 coli in some properties, but it failed to ferment lactose. 



Bacillus subtiUs, B. radiciformis, proteus, sarcinte, yeasts, and 

 molds were occasionally met with in milk directly from the udder. 



Esten and Mason describe the following organisms which they 

 found in milk directly from the udder: 



VARIETIES OF UDDER ORGANISMS FOUND IN COLLEGE HERD AT STORRS 



Name. Frequency. Liquefaction. Acidity. Color. 



Micrococcus lactis acidi 22 — + White 



Micrococcus lactis albidus 9 + + White 



Micrococcus lactis albidus, variety B 8 — — White 



Micrococcus lactis varians 7 + + Yellow 



Micrococcus lactis aureus 3 — -j- Yellow 



Bacillus subtilis, variety B 3 + — White 



Bacillus subtilis 2 + — White 



The authors state that Micrococcus lactis acidi which was found 

 twenty-two times is the most common of the milk cocci, and is 

 almost constantly found in fresh milk. It "is classified very near 

 Streptococcus lacticus, which is the same as Bacterium lactis 

 acidi. It is even considered a variety of Streptococcus lacticus 

 III." The nomenclature is that of Conn's Classification of Dairy 

 Bacteria. 



Harding and Wilson in an extensive study of the udder flora 

 separated 71 distinct groups of organisms from over 900 samples 

 of milk. Of these, 75 per cent, were micrococci. Streptococcus 

 lacticus was found occasionallj'. The authors suggest that strep- 

 tococci would be more frequently discovered if special media, 

 favorable to their growth, were employed. Two non-sporing 

 yeasts were also isolated. Spore-forming bacteria were wholly 



