Electrocardiogram of Cretin Sheep. 425 



Learning the Labyrinth with the Position of the Cul de Sac Reversed. 





Total No. 



Total No. 



Total No. 



Total 





of Trials. 



of Errors. 



of Steps. 



Time. 



Normal Lamb 



7 



4 



3254 



801 sec. 





4 



12 



47io 



2319 sec. 



Tests on the remaining pair were begun two hundred seven 

 days after the operation with the following results : 



Relearning the Simple Labyrinth. 





Total No. 



Total No. 



Total No. 



Total. 





of Trials. 



of Errors. 



of Steps. 



Time. 



Normal Lamb 



5 



11 



2808 



911 sec. 



Cretin Lamb 



4 



5 



3312 



450 sec. 



Learning the Labyrinth with the Position 



OF THE CUL 



de Sac Reversed 





Total No. 



Total No. 



Total No. 



Total 





of Trials. 



of Errors. 



of Steps. 



Time. 



Normal Lamb 



8 



5 



4804 



828 sec. 



Cretin Lamb 



4 



9 



3553 



1375 sec. 



A more difficult problem was then presented to this pair. The 

 position of the cul de sac was alternated during four successive 

 trials per day and twelve trials without error were required for 

 complete learning. Three hundred thirteen days after thyroid- 

 ectomy the cretin completed the problem in two hundred twenty 

 trials while the normal lamb required but one hundred fifty-six 

 trials. 



The expense of this investigation was defrayed by grants from 

 the Heckscher and Sage Research Foundations. 



208 (1955) 



The characteristic electrocardiogram of the cretin sheep. 



By STANLEY ROSS BURLAGE (by invitation). 



[From the Electrocardiographic Laboratory, Department of Physi- 

 ology, Cornell Medical College, Ithaca, N. Y.] 



In November, 1921, the writer made routine electrocardio- 



