STRUCTURE AND DEVELOPMENT OF BACTERIA 



2 5 



cell-wall dissolves gradually or stretches and allows the spore 

 to be set free. 



Each bacterium gives rise to but one spore. It may be at 

 either end or in the middle (Fig. 4). Some rods take on a 

 peculiar shape at the site of the spore, making the rod look 

 like a drum-stick or spindle clostridium (Fig. 5). 



Spore Contents. What the real contents of spores are is 

 not known. In the mother-cell at the site of the spore little 

 granules have been found which stain differently from the rest 



Fig. 4. Sporulation (after De Bary). 



Fig. 5. Clostridium. 



of the cell, and these are supposed to be the beginnings the 

 sporogenic bodies. The most important part of the spore is 

 its capsule; to this it owes its resisting properties. It con- 

 sists of two separate layers a thin membrane around the 

 cell, and a firm outer gelatinous envelop. 



Germination. When brought into favorable conditions, 

 the spore begins to lose its shining appearance, the outer firm 

 membrane begins to swell, and it now assumes the shape and 

 size of the cell from which it sprang, the capsule having burst, 

 so as to allow the young bacillus to be set free. 



Requisites for Spore Formation. It was formerly 

 thought that when the substratum could no longer maintain 



