AUXETICS AND AUGMENTORS 



41 



again prepared, the solutions in this case being 

 as follows : 



A contained 0'005-per-cent. choline. 

 B contained 0'2-per-cent. choline. 

 C contained distilled water. 



The average number of amoebae in 50 fields at the 

 beginning of the experiment was in A 5, in B 7, 

 in C 5 amoebse per field. Recounts were made 

 after twenty-four hours, and gave: 



A. 13 amoebae per field. 

 x>. 18 ,, ,, ,, 



Recounts after three days gave : 



A. 25 amoeba? per field. 



B. 42 



C. 10 



Judging from these figures the choline stimulates 

 multiplication very rapidly. In both A and B the 

 average number of amoebae per field was more than 

 doubled in the first twenty-four hours, and about 

 doubled again in the following two days. In the 

 control scarcely any increase took place in the 

 first twenty-four hours, and subsequently two days 

 were taken before the numbers were doubled. It 

 will be observed that 0'005-per-cent. choline was 

 nearly as effective as 0'2-per-cent. Partly with 

 the object of repeating the above experiment, it 

 was decided to make an absolute count of all the 

 amoebae on the live slide. A uniform suspension of 

 amoebae was made in 5 cc. of distilled water. Two 

 very small cover-glasses were then taken, and an 



