IDENTITY OF THE LACTIC-ACID STREPTOCOCCUS 157 



saved for study. The fifty cultures selected came from the 

 milks of seven individual cows and from the mixed herd milk 

 as follows: 



Culture Numbers From Cow 



51 to 63 663 



54 to 60 337 



61 to 66 459 



67 to 72 631 



73 to 77 734 



78 to 83 620 



84 to 90 624 



91 to 100 mixed herd milk 



All of the animals from which these samples were obtained 

 were in a healthy condition, except cow 459, which was suffer- 

 ing from a case of mammitis. 



MORPHOLOGY 



Microscopic examinations were made of all of the 100 cultures 

 on agar, broth and bile. Although no hard and fast rules can 

 be given, it may be said from this study that on agar and broth 

 the group of organisms numbered from 1 to 50 showed a greater 

 tendency to form elongated cells than did the others. Also the 

 typical grouping, that is the grouping of the majority of cells, 

 was usually in pairs rather than in definite chains. But chain 

 formation was common in these cultures, and in some of them it 

 was the predominating grouping. The grouping in pairs was 

 frequent among the cultures numbered from 51 to 100, but in 

 all of these the typical arrangement was in chains. 



The results obtained from growth on lactose-peptone-bile were 

 surprising in that the lactic-acid cultures made a much more 

 luxuriant growth than did the udder streptococci. On this 

 medium the lactic organisms grew in long chains and appeared 

 as typical streptococci in every way. In only one of these 

 cultures on bile were as many cells arranged in pairs as were 

 present in chains. This is of special interest in view of the fact 

 that many health laboratories use bile as a presumptive test for 

 the presence of undesirable streptococci in milk. Kinyoun 

 and Dieter (1912) consider that the formation of chains in bile 



