CHAPTER X. 



FORMATION AND GERMINATION OF SPORES, AND METHODS OP 

 STAINING THBM. 



Many bacteria have the power of entering into a rest- 

 ing or permanent condition when they form the so- 

 called spores, which, when they develop inside of the 

 vegetative bacterium cell, are called endospores. 

 Sometimes, however, some or all of the members of 

 a collection of cells or of a colony are changed 

 directly into resting cells, and these are termed arthro- 

 spores. 



These arthrospores occur much less frequently, and 

 are much less conspicuous, than the endospores; more- 

 over they do not possess the same characteristics, it 

 being often very diflBcult to distinguish them from the 

 ordinary vegetative cells. In addition, it is not ofte^ 

 easy to get material containing them for examination, 

 so we will leave them without further consideration, 

 and will only consider the endospores, which for the 

 sake of brevity we will call sporen. 



The best original material for the examination of 



spores is afforded us by the bay bacillus, concerning 



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