BEHAVIOR OF STOCK AND INBRED ALBINO RATS 277 





5 10 IS 20 25 



Figure 4. — Short maze. Errors. Stock, — — - ; inbred, 



required more than the allotted limit of fifteen minutes in order 

 to complete the first trial. The time, however, immediately and 

 rapidly decreased and remained low and fairly regular. The 

 inbred rats, on the other hand, spent the full time allowed in 

 the first two trials sitting in corners, and did not reach the 

 centre at all. The distance and error records were therefore 

 very low at the beginning, but increased as activity increased. 

 The amount of time correspondingly increased, but in much 

 greater degree and with great irregularity. The curves which 

 were plotted for these records but are not reproduced show for 

 the inbred rats sharp variations from day to day in time re- 

 quired for each trial between the tenth and thirtieth trials and 

 high records obtained. After the thirtieth trial the time was 

 only a little greater, while distance and error records for the 

 inbred rats were on the whole lower than those for the stock 

 rats. The inbred females also acquired a perfect habit sooner, 



