HABIT FORMATION IN ALBINO RATS 



23 



TABLE IIIc— (Continued) 



Day 11 Day 12 Day 13 Day 14 



Control +B 5.935 5.750 5.740 5.700 



Control— B 5.223 5.223 5.223 5.223 



Day 16 Day 17 Day 18 Day 19 



Control +B 7.090 5.725 5.890 5.550 



Control— B 5.223 5.223 5.223 5.223 



Day 21 Day 22 to Day 50 



Control +B 6.200 5.415 



Control— B 5.223 5.223 



Failed Days Required 



to Relearn to Relearn 



Control +B 8.24 



Control— B 4.08 



Day 15 

 5.835 



5.223 



Day 20 



5.765 

 5.223 



TABLE Illd 

 The Maze i 



Anatomical Data of +B and — B Normal Control Rats 



Cord 



Weight 



in grins. 



.54191 



.51643 



Body Body Brain 



Length Weight Weight 



in mm. in grms. in grms. 



Control +B 193.00 175.73 1.75378 



Control— B 189.50 168.18 1.75428 



Water Per cent Per cent 



in Cord, Brain Weight Brain Weight 



Per in Relation to in Relation to 



cent Body Length Body Weight 



Control +B 71 .48 .90406 1 .02303 



Control— B 71.81 .92748 1.07861 



Water 

 in Brain, 

 per cent 



78.25 



78.37 



Age 

 killed, 

 Days 



200 

 175 



In Plate V is shown the curve of learning (below) and of 

 relearning (above) of the inbred and +B rats compared with 

 those of the — B. The inbred curve is represented by the solid 

 line, the +B by the heavy broken line, and the — B by the 

 lighter broken line. The ordinates show the average daily time 

 in seconds for each group, and the abscissae the number of the 

 day in which such time was made. From the twentieth day the 

 — B curve is flat at 4.9 seconds. Neither the inbred nor the +B, 

 curves flatten entirely, although the +B curve of learning is 

 more regular than that of the inbreds. The curve of relearning 

 (lacking the two inbreds and one +B that failed to learn) shows 

 little difference between the three groups. But even here, 

 although the inbred and +B are selected groups, the — B re- 

 mains superior to both, and the +B is slightly superior to the 

 inbred rats. 



