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K. S. LASHLEY 



influence of strychnine than while normal. In group 3 only 

 one of the rats (no. 4) made fewer errors when under the in- 

 fluence of caffeine than when normal and this rat totaled so 

 many more errors than any of the others that his, record may 

 perhaps be regarded as abnormal. This result agrees with the 

 data on learning. The animals which learned most rapidly, 

 those under the influence of strychnine, also were most accurate 

 in carrying out the learned activity. Those which required 



TABLE 12 



Individual records of efficiency of performance in animals receiving doses of strych- 

 nine sulphate or caffeine alternately with water 



much practice for perfect learning were inaccurate even after 

 having once acquired the required standard of proficiency. It 

 seems that the same factors that resulted in increased or di- 

 minished accuracy in performance of the perfected habit were 

 influential also in shortening or prolonging the learning process. 



DISCUSSION 



We may summarize the better established results of this 

 work as follows: Strychnine sulphate, when administered in 

 doses large enough to produce obvious changes in tonus, effects 



