to the failure to supply certain substances which are 

 necessary for proper nutrition. An attempt was therefore 

 made to provide an adequate medium for the primitive an- 

 imal cell, Ameba proteus. 



Since amebas were found to move m.ore norm.ally and 

 to live longer in distilled v/ater to which had been added 

 one- tenth the volume of spring water, this "10''^ spring 

 water" was used in making up all solutions. 'Various car- 

 bon compounds, including several sugars, were nov/ tested 

 with the hope of finding a source of energy. 



The method used vas as follows: A number of amebas 

 were selected from the same culture, and freed from food 

 and bacteria by transferring repeatedly to fresh solutions 

 of lOfJ spring water. They were then transferred to slides, 

 piecing 10 in 10"^ spring water as a control, and 10 in 

 each of the solutions to be tested. The anim.als were 

 examined and counted each day, washed in water, and trans- 

 ferred to fresh solutions to prevent the development of 

 bacteria. The most promising substances found were the 

 hexoses, glucose and levulose, t>-e effect of which may 

 be seen by the following experiments: 



(33) 



