CONSTANT DIFFERENTIAL GROWTH-RATIOS 5 



here of no particular biological significance, since it merely 

 denotes the value of y when x = 1 — i.e. the fraction of x 

 which y occupies when x equals unity. We may call it the 



3000 



I 



^2000 



I 



•is 



"a 

 1000 



500 



100 



J 000 5000 10,000 15,000 



size of body 



-3000 



2000 



1000 



Fig. 1. — Diagram to show the quantitative effect of varying the constants 



in the simple heterogony formula, y = bx k , assuming that the origin of growth 



in x and y begins at the same time. 



The dotted line gives the growth of the organ (y) when k = 2-0 and b = -ooooi. The points to 

 the left show values of y for different values of b when the rest-of-body is of size 1000. Those to the 

 right show the effects, at body-size io,ooo, of varying both k and b. 



