THE STORY OF GERM LIFE. 



ing little water, and they do 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 

 activity even after 

 the spores have 

 been produced. 



A r t h r ogenous 

 spores (?). Certain 

 species of bacteria 

 not produce spores as just described, but 



FlG. 12. Endogenous spores: a and 

 b, Spores forming at intervals in 

 the rods ; c, Spores forming in the 

 middle of the rods and causing the 

 middle to swell ; d, Spores form- 

 ing at the end of the rods and 

 causing the end to swell. 



do 



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 



