GENERAL MORPHOLOGY AND PHYSIOLOGY OF BACTERM.. 



29 



somewhat, depending on temperature, moisture, and food supply. The 

 average life of one individual (from septation to septation) is perhaps thirty 

 minutes. Under favorable condition the period is much shortened. This life 

 period of the individual cell must not be confounded with the life cycle of the 

 individuals resulting from a single cell or parent. It is known that under 

 uniform conditions of temperature, moisture, food supply, and the environ- 

 ment generally, the progenations from a single parent cell show an increasing 

 rate of septation, a stationary period, followed by a gradual decline, ending 

 in total cessation of all septation, and in death. These life cycles have not 



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t)V, ^^>Aa 



/ 



s. 





Fig. 10.— Illustrating zooglea formation, a. baciUar aggregates resultmg frorti 

 cohesion; b, aggregates resulting from cohesion of bacilli with gelatmized cell-walls; c, 

 streptococcus formation resulting from the septation of a coccus form; d, cohenng cocci 

 forms; e, bacilU united end to end (resulting from septation), enclosed m a gelatinous coat; 

 /, baciukr thread enclosed in gelatin; g, mycobacterial form; h, irregular ceU forms, as 

 Mycoderma aceti. 



yet been carefully determined; in fact, they are but little understood. It is 

 highly-probable that the cycles of existence play a very important part in the 

 course and development of diseases of bacterial origin. 



Whereas the period from one septation to another septation is very short, 

 the life cycle referred to is often quite long, perhaps months and, under 

 certain conditions, lasting for years. The period of the life cycle can be 

 modified artificially by food supply, chemicals, etc. 



