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K. S. LASHLEY 



fixed but never completely disappeared. The fact, brought out 

 in table 11, that with long training their rate of running under 

 the influence of the caffeine became less than without the drug 

 is due to the fact that more errors were made under the former 

 conditions and more time was lost in turning and other activities 

 which did not increase the distance traversed. 



THE EFFECT OF THE DRUGS UPON EFFICIENCY OF PERFORMANCE 



OF A MOTOR HABIT 



For further information which might be of service in inter- 

 preting the data on learning a series of tests upon the effect of 



TABLE 11 



Data on the effects of strychnine and caffeine on efficiency in the performance of a 



motor habit. The averages (except those marked first ten trials) are 



each based upon 180 trials 



the drugs upon the established maze-habit was carried out. 

 Eighteen rats which had learned and relearned the maze were 

 divided into three groups and given five trials per day in the 

 maze for fourteen successive days. On the first two days all 

 were given subcutaneous injections of 0.10 cc. of water ten 

 minutes before they were started in the maze. A comparison 

 of their efficiency with and without the drugs was then made in 

 the following way. For two consecutive days the drug was 



