FACTS AND FACTORS OF DEVELOPMENT 51 



FIG. 18, a, b, c. REPULSION OF Spirilla BY COMMON SALT. 

 a, condition immediately after adding crystals; b and c, later 

 stages in the reaction. 



x, y, z, repulsion of Spirilla by distilled water. The upper 

 drop consists of sea-water containing Spirilla, the lower drop, 

 of distilled water. At x these have just been united by a 

 narrow neck; at y and z, the bacteria have retreated before the 

 distilled water. (From Jennings, after Massart.) 



