BEHAVIOR OF STOCK AND INBRED ALBINO RATS 295 



SUMMARY 



1. Almost an equal number of stock and inbred rats, because 

 of excessive inactivity, could not be used in the experiments. 



2. In the long maze, the male stock rats traveled greater 

 distances, took longer times for the trials, and made more errors, 

 but acquired a perfect habit sooner than the inbred males. 



3. In the long maze, the female inbred rats traveled greater 

 distances, took longer times for the trials, and acquired the 

 habit sooner than the stock females. The irregularity in the 

 records is greater. The time records are very high in com- 

 parison to distance and errors. 



4. When males and females are averaged together, the stock 

 rats show a smaller number of trials required to form a perfect 

 habit than the inbred (55.25 as against 65.00). 



5. In the short maze the stock rats acquired the habit sooner 

 than the inbred rats (19.2 as against 23.75). 



6. In the short maze the time records are relatively high for 

 the inbred rats, especially during the first few trials. 



7. There is greater irregularity in distance and error records 

 for the inbred rats. 



8. In the discrimination apparatus all the rats showed a 

 greater preference for the dark than for the light box. 



9. The inbred rats showed this preference more markedly 

 than did the stock rats. 



10. All the rats learned to discriminate the lighted from the 

 dark box when the difference in illumination was great, and to 

 choose the lighted one in opposition to their preference for the 

 dark one. 



1 1 . The inbred rats required a larger number of trials than 

 did the stock rats in order to perfect the habit of choosing the 

 light box. 



12. The inbred rats continued to be able to discriminate 

 under more difficult conditions than did the stock rats. 



13. The inbred rats showed a brain weight in relation to 

 body length very slightly less than that of the normal rats, 

 and the same is true of the relation of brain weight to body 

 weight. 



