ro 



DAY AND BENTLEY 



eliminated by experimental control, it was impossible to ascribe 

 the changes observed to conscious, or even to purely organic, 

 conditions. A number of subjects were transferred, therefore, 

 at the end of the test, to an open watch-glass of culture-water; 

 then after an interval of ten to twenty minutes they were re- 

 placed in the capillary-tube and observed as before. In this 

 way the animal was brought for a second trial under the same 

 external conditions as at first. If the first reduction of times 

 and turns was owing to the environmental changes which we 

 have just assumed to exist, then we might expect the second 

 performance to repeat the first. On the other hand, if the 

 individual had really " learned " during the first trial, we might 

 well look for subsequent modification. The curves, figure i, 

 give the results (number of partial turns before each successive 

 reversal) for six new^ subjects. A, B, C, M, Q, and R. In the 

 case of C, we succeeded in carrying the individual through a 

 third test after a second interval of thirty minutes. 



Tables III, IV, and V are designed to interpret the curves 

 of figure i. They give the number of reversals in each phase 

 of the curve, together with the average number of partial turns 

 or " trials " necessary to a single reversal. 



TABLE III 



