284 E. C. MACDOWELL AND E. M. VICARI 



in the two groupings of the trials, the first half of training and 

 omitting the first day. The averages for each day have not been 

 calculated. 



8. The difference between the tests and controls in the number 

 of errors depends upon two of six types of errors. The tests 

 make more errors of types 1 and 2, but there is no real difference 

 in the numbers of errors of the other four types made by the 

 tests and controls. 



9. The tests required three more trials on the average to 

 eliminate errors of type 1; the tests required one more trial to 

 eliminate, errors of type 2. The other types of errors were 

 eliminated in about the same number of trials by each group. 

 This is based on the averages of the number of trials before each 

 rat eliminated each type of error; an error was said to be elimi- 

 nated when it occurred only once in four successive trials. 



10. Seven more tests than controls failed to eliminate errors 

 of types 1 and 2 ; the only rat failing to eliminate the other types 

 of errors was a control. 



11. The tests made fewer perfect trials than the controls. 

 This statement is based on the average numbers of perfect 

 (errorless) trials in training and retention separately. 



12. The tests required more trials before making the first 

 perfect trial than did the controls. 



13. The tests spent more time in running their perfect trials 

 than did the controls; this is based on the average time spent on 

 perfect trial by the two sets of rats. 



We believe that the above points show that the test and con- 

 trol rats differ, as groups, in their behavior in the maze. From 

 the standpoint of learning their way to the center and going 

 there for food, the tests are less successful than the controls. 

 The alcoholic treatment of the grandparents is the only basis 

 upon which the rats have been divided into the two groups of 

 tests and controls; therefore the alcohohc treatment appears 

 to be responsible for the inferiority of the tests in running the 

 maze. If this is true, a modification of the genetic basis of 

 inheritance is demonstrated. 



Cold Spring Harbor, 

 July. 1920 



