2b STREPTOCOCCI 



or less influenced b^-its conditions of life. When, for example, 

 two streptococci appear to be identical under the majority of 

 tests, a slight deviation in a single property- cannot be considered 

 of great differential value especially if this particular manifesta- 

 tion is among these most subject to change. A fundamental diffi- 

 culty in differentiating species among streptococci seems to be a 

 lack of information concerning the possible variations brought 

 about by different environments. The further difficulty of 

 identifying any of the very large number of forms which have 

 been assigned specific names is due to the brevity- of their de- 

 scription and the failure of the author to mention any character 

 or property, or combination of the same, which would distin- 



••• ; 



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•••• 

 4. S. 6 



Fig. 4. Six forms of dreptococci. r. Long chains consisting of 

 small scgmenh arranged with cqnal spaces between them. 2. Long and 

 shorter chains in which the segments are arranged in pairs. The size of 

 the individual segments is considerably larger than those in the long 

 chains, s- Short and longer chains where the segments are oval with the 

 long diameter perpendicular to the long axis of the chain. 4. Long 

 interlacing chains. 5. Short and longer chains with one or more seg- 

 ments very much larger than the others. 6. Chains showing divisions 

 in two planes. This form of division has been ohs'erved m a few cases. 

 The dividing in two planes is an exception which is not satisfactorily 

 explained . x about 1000. 



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