BACTERIA 



21 



known. In the mother-cell at the site of the spore little gran- 

 ules have been found which stain differently from the rest of 

 the cell, and these are supposed to be the beginnings the sporo- 

 genic bodies. The most important part of the spore is its cap- 

 sule; to this it owes its resisting properties. It consists 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 mem- 

 brane begins to swell, and it now assumes the shape and size 



Fig. 5. Sporulation (after De Bary). 



Fig. 6. Clostridium. 



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 it, or had 

 become infiltrated with detrimental products, the bacterium- 

 cell produced spores, or rather turned itself into a spore to 

 escape annihilation; but we believe now that only when con- 

 ditions are the most favorable to the well-being of the cell, 

 does it produce fruit, just as with every other type of plant or 

 animal life, a certain amount of oxygen and heat being neces- 

 sary for good spore formation. The question is still unsettled, 

 however. 



