10 



Tables la and Ila shov/, vesxjectively , the aaily a,v- 

 erai^e time in seconils of the inbred and normal control series 

 durinej the process of formation of the naze habit, Aft^r the 

 standard set for perfection (five perfect trials of six sec- 

 onds or less each, for each of three consecutive dayg) htid 

 been reac'ied, t]ie average time of the three perfect days was 

 carried on for the succeeding days in red ink. For example, 

 in Table la, the ti>ie record of rat 6B10?c? is recorded thus; 

 day 10, 5.12 seconds; day 11, 4.92 seconds; day 12, 5.04 sec- 

 onds. The average of these three perfect days, 5.03 seconds, 

 is carried forward in red ink. It is necesgary to preserve 

 these figures in order to compute the total daily averat;es 

 based upon which the curves of learning; are constructed. 



Table lib, the daily averas^es of the control series, 

 is especially significant showing, as it does, the erratic 

 behavior of the B strain. By the end of the twenty-fourth day 

 all the normal group had formed the perfect raar.e habit with 

 the exception of five rats from the 3 strain; nor did any of 

 these five become perfect until a week later v/hen two dropped 

 out. One B rat persisted in the same error, pas3in<^ entrance 

 2 into the cul-de-sac at the right, with occasional other er- 

 rors and did not learn the problem in the hundred days allow- 

 ed. 



Tables lb and lib show what I have termed the abso- 

 lute retention of, respectively, the inbred and normal control 

 series. Absolute retention is -aeasured by the time required 

 to complete the firs t trial of the relearninj^; series after 

 the sixty days' rest; the stronger the retention, the less 

 the time. These tables show the absolute retention of the nor- 

 mal control series to be much stronger than that of the inbred, 



Tables Ic and lie show, respectively, the daily av- 



