22 AMCEBA LESS. I 



terious effects of an excess of salt are produced only when 

 the salt is added suddenly. By the very gradual addition of 

 sodium chloride Amoebae have been brought to live in a four 

 per cent, solution, i.e., one twice as strong as would, if added 

 suddenly, produce dry-rigor. 



From what has been said above on the subject of respira- 

 tion (p. 17) it follows that free oxygen is necessary for the 

 existence of Amoeba. Light, on the other hand, appears to 

 be unnecessary, amoeboid movements having been shown to 

 go on actively in darkness. 



