248 



J. ARTHUR HARRIS AND H. S. REED. 



practically attained its adult size and in which there is relatively 

 little change from one week to another. 



As we follow the correlations between the later periods and 

 preceding periods back, we note that there is a regular decrease 

 in the values of the correlation coefficients. This may be best 

 shown by summarizing the results graphically in diagram I. 



In the graph the correlation of the size of the organism at each 



l-o 



3 

 8 



14- Zl 28 35 42. 49 



AGE OF PLAA/T (STAGE) 



DIAGRAM i. 



56 63 



70 



growth stage with its size at every antecedent growth stage (shown 

 at the bottom of the diagram) is shown on the scale of correlation 

 at the left by points marking the magnitude of the correlations 

 for each of the growth stages. The pitch of the lines connecting 

 the points for the i_j.th to the 77th growth stage shows the rapid 

 decrease in the magnitude of the correlations as the stages be- 

 come more widely separated in time. 



