30 



K. S. LASHLEY AND L. E. WILEY 



of order in the fifteen series of constants. This is conclusive 

 evidence of a continuous relationship between the extent of 

 injury and the degree of retardation. 



Previous data (Lashley, '29; Maier, '32) have suggested 

 that there may be a limit of size below which lesions are rela- 

 tively ineffective and above which there is marked defect. In 

 these more adequate data there is no indication of a con- 

 sistent, marked flexion point between any two of the class 



TABLE 15 



Mied after 119 trials. 



intervals. It is very probable that where such a condition 

 has appeared in earlier data, it has been due to chance varia- 

 tion in inadequate samples. 



With the limited data heretofore available, it has not been 

 possible to define the form of the relationship between extent 

 of lesion and degree of retardation. Lashley 's data ('26, 

 '29) indicate that extensive lesions produce a disproportion- 

 ately great effect. Thurstone ('33) has concluded from an 

 analysis of the original data that the formula k = aC 6 , where 



