16 



AGRICULTURAL BACTERIOLOGY 



has been found to occur in twenty minutes. Such a rapid 



rate is attained only un- 

 der the most favorable 

 conditions of food and 

 temperature. 



This cell division is 

 termed vegetative repro- 

 duction, in contrast to 

 a second method that is 

 found in a small number 

 of the bacteria, viz., re- 

 production by the for- 

 mation of spares. In 

 this process a portion of 

 the protoplasm is con- 

 densed in one part of 

 the cell to form a small 



spherical or oval, highly refractile body, to which the term 



Fig. 6. Spirilla 



The organism causing recurrent fever. The 

 cells show many turns instead of only a 

 portion of a turn as in the cholera organism 

 After Gunther. 



Fig. 7. Spores 



A portion of the content of the cell is condensed into a body which appears very 



bright under the microscope. On germination a rod similar to the one that 



produced the spore results 



endospore is applied. The production of the spore is fol- 

 lowed by the death of the cell and its dissolution, so that the 



