19 

 "but more days*than the rats given five trials a day. 



What is significant in this statement is that when a rat 

 is given one trial a day there is a saving in trials, and, 

 on the other hand, when more trials are given there is 

 usually a saving in the number of days. 



Before taking up the particular curve which shows 

 the growth in the organization of primal or impulsive 

 movements in the learning of the latch box problem, it 

 would be well to describe, at this stage, the structure 

 of all curves of this sort. All are plotted on the same 

 scale. The time taken is the average time of trials of 

 all rats. A length of one-half m.m. on the abscissa rep- 

 resents one trial and one-half num.. on the ordnant rep- 

 resents for curves A and G ,006 Of a minute and curve 

 B 0.2 of a minute. Both on the abscissa and the ordnant 

 only every tenth trial or every tenth .006 or 0.2 of a 

 minute are respectively indicated. The ea^ly trials are 

 on a scale of 0.2 of a minute, and later trials .006 of 



