DEFINITION, MORPHOLOGY, AND PHYSIOLOGY 17 



Non-motile bacteria are those forms which do not 

 possess the power of locomotion. ; , 



Reproduction. In common with all living organisms, 

 bacteria possess the power of reproducing their kind 

 and in keeping with their uncomplicated structure; 

 their mode of reproduction and multiplication is corre- 

 spondingly simple, namely, by fission or simple trans- 

 verse division. 



Fission, the process of bacterial reproduction, takes 

 place as follows: The cell elongates, an indentation 

 occurs in its wall, which gradually increases in depth 

 until the cell is completely divided, and two cells take 

 the place of one. 



Sporulation. Under certain conditions of heat, light, 

 oxygen, etc., conditions detrimental to bacterial activity, 

 there occur in some bacteria glistening, highly refractive 

 bodies termed spores. These are surrounded by a tena- 

 cious membrane or capsule, and when the spore is 

 fully developed the remainder of the bacterium disin- 

 tegrates and disappears. These bodies are supposed to 

 represent the seed or resting stage of the plant's existence 

 and is a means whereby the organism resists deleterious 

 influences. It is not, however, a means of multiplica- 

 tion as in the higher plants, as each bacterium produces 

 but a single spore, which, under favorable conditions, 

 again develops into a complete bacterium, which may 

 multiply in the usual manner by division. 



Owing to the tenacious character of its membrane the 

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