\'ARlAT10i\' AM) CuRKliLATION IX TiMOTHY. 469 



Changes in the coefficient of correlation are evidently due to the 

 same causes that are instrumental in producing skewness. 



Place variation must be taken into consideration in any study of the 

 condition of a given species; only confusion can result from conclusions 

 based on momentary states of the population. 



In the practice of selection, place variation should be recognized as a 

 factor, at least so far as those characters are concerned which respond 

 readily to environmental influences, and each individual, including 

 its progeny in the case of annuals, kept under observation for a sufficient 

 period to eliminate errors due to this cause. 



