26 



THE STORY OF GERM LIFE. 



ing little water, and they da not so readily absorb 

 staining material as the ordinary rods. They ap- 

 pear to be covered with a layer of some substance 

 which resists the stain, and which also enables 



them to resist vari- 

 ous external agen- 

 cies. This protect- 

 ive covering, to- 

 gether with their 

 small amount of 

 water, enables them 

 to resist almost any 

 amount of drying, 

 a high degree of 

 heat, and many 

 other adverse con- 

 ditions. Common- 

 ly the spores break 

 out of the rod, and 

 the rod producing 

 them dies, although 

 sometimes the rod 

 may continue its 

 FIG. 12. Endogenous spores : a and activity even after 



b, Spores forming at intervals in f i cn nr^c hav^ 



the rods ; c, Spores forming in the tne s P ores nave 

 middle of the rods and causing the been produced, 

 middle to swell ; d, Spores form- A r t /I r OgeHOUS 



ing at the end of the rods and ,^ 



causing the end to swell. Spores (?). Certain 



species of bacteria 



do not produce spores as just described, but 

 may give rise to bodies that are sometimes called 

 arthrospores. These bodies are formed as short 

 segments of rods (Fig. 130). A long rod may 

 sometimes break up into several short rounded 

 elements, which are clear and appear to have a 

 somewhat increased power of resisting adverse 



