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CARNEGIE INSTITUTION OF WASHINGTON. 



records of the paths taken by the rats. Two large-sized mirrors are suspended 

 over the maze in such a way that the rays of Hght from the illuminated maze 

 are twice reflected and passed through a lens in the top of a small camera- 

 box. Inside this box the image of the maze is projected upon the record 

 sheets. As a rat travels about in the maze its image is followed with a pencil 

 on the record sheet, and in this way an accurate record of every trial is 



obtained. These lines are subsequently measured with a chartometer, so 

 that the distances traveled may be calculated. The time per trial is also 

 recorded. Although 29 rats have been tested on this maze, no statement of 

 results can be made at present. 



"As the rats grew to be more than a year old, there appeared a very high 

 incidence of tuberculosis, so that in many of the experiments the maze and 

 memory test could not be made. 



Summary of rat training, 1916-16. 



"As it became more and more evident that the alcohol taken in by the 

 parents had not made any very striking modification in their children, plans 

 were made to start a second group of experiments in which the amount of 

 alcohol administered should be greatly increased. A start has been made on 

 this work with 8 pairs of rats, which are being made dead drunk every day. 

 There has been developed a much shortened and standardized system of train- 



