210 E. C. MACDOWELL AND E. M. VICARI 



4. Comparison of the test and control rats on the basis of the rate of 



running (speed) 265 



5. Comparison of the test and control rats on the basis of the numbers 



of errors 268 



a. All types of errors together 268 



b. Each type of error separately 270 



c. The number of trials before each type of error was eliminated. . 272 



6. Comparison of the test and control rats on the basis of perfect trials. 275 



a. Number of perfect trials 275 



b. Number of trials before the first perfect trial 277 



c. Time spent in running perfect trials 277 



Discussion *. 280 



General summary 281 



Appendix 285 



INTRODUCTION 



The following experiments have been carried on primarily to 

 try to control or modify inheritance. It must be made clear in 

 the beginning that whatever human relation they have is inci- 

 dental. The human interest is more especially aroused by the 

 chemical used than by any parallelism of the kinesthetic behavior 

 of rats in a maze and the moral behavior of man. On the other 

 hand, if it can be proved that alcohol does occasion changes in 

 the normal inheritance of rats, as shown even by such an ele- 

 mentary type of behavior as learning a maze, a great field of 

 possibilities is at once opened up; other modifications of inheri- 

 tance, by means of the same or other chemicals, may be brought 

 about in other animals, including man. 



The general plan of the work undertaken has been to study 

 the habit-forming abilities of rats in successive inbred genera- 

 tions following one generation treated with alcohol. For a 

 standard or control the inbred descendants of the normal brothers 

 and sisters of the alcoholized rats have been used. Preliminary 

 studies indicated that strong doses would be required if any 

 influence upon the germ-plasm is to be expected. For this reason 

 the maximum exposure to alcohol fumes has been employed in 

 the treatment of the grandparents of the rats whose training is 

 the subject of the present paper. The results appear to indicate 

 that inheritance can be modified to a certain degree by alcohol. 



