156 



K. S. LASHLEY 



of those receiving the larger dose of strychnine were superior 

 to their controls. This comparison of individuals eliminates 

 the excess weight given to extreme variates by the computation 

 of averagers and forms a basis for an estimation of the regularity 

 of action of the drug. The results are consistent with those 

 obtained from the averages of trials and distances and lend 

 additional support to the view that the superiority of groups 

 A and E over their controls is the result of the action of the 

 drug and not merely a chance variation. 



The evidence from various sources, when massed together, 

 seems dependable. The animals receiving the smaller dose of 

 strychnine were not affected by the drug. The larger animals 

 showed little effects of the drug either upon their general tonic 



TABLE 4 



The proportion Qf rats receiving strychnine which learned the maze in fewer 

 trials than their individual controls 



condition or their rate of learning, with the exception of two 

 which showed tremor and learned more rapidly than the other 

 members of the group. The smaller rats, after the large dose 

 of strychnine, showed a fine tremor and learned the maze in 

 considerably less time than was required by the controls. The 

 evidence points to an acceleration of learning resulting from 

 the administration of strychnine, but only when it is given in 

 doses large enough to produce observable alterations in muscular 

 tonus. 



Time of action of the drug. To test whether the acceleration 

 is due to the immediate effects of the drug or to a general altera- 

 tion in metabolism another series of rats was trained in which 

 the strychnine was administered daily five minutes after train- 

 ing instead of before,. The results of this test are given in table 



