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K. S. LASHLEY 



receiving the smaller dose of strychnine is not significantly 

 different from 'that receiving water only. Judged by the 

 standard of the first errorless run it is superior, by that of 

 three errorless runs it is inferior. In neither case is the differ- 

 ence enough greater than its probajble error to be significant; 

 there is no indication that the strychnine had any effect upon 



FIG. 1. A comparison of the number of trials required for learning by animals 

 trained after injection of strychnine and normal animals (receiving injections of 

 water only) . The squares represent each one animal ; the diagonal lines indicate 

 females. For each group the number of animals making each score is shown 

 on the ordinates, the number of trials required for learning on the abscissae. 

 The dotted lines show the averages of the groups. 



the learning of this group. The heavier dose of strychnine, 

 on the contrary, seems to have reduced the number of trials 

 required for learning. A comparison of group A with the con- 

 trol group D shows, as a probable result of the administration 

 of the strychnine, a reduction of 36 to 44 per cent in the num- 

 ber of trials required to meet the two criteria of learning. Both 



