436 



ON INCREASE IN SIZE 



[PT. Ill 



he proceeded a good deal further along it by observing that the 

 graph relating instantaneous percentage growth-rate to age was 

 practically identical with a rectangular hyperbola, and that there 

 was a simple relation between the values of r or Cv (Brody's K) and 

 the age, for the product of the two was always roughly equal to 300.* 



Table 56. Embryonic growth: Schmalhauseri's '■^Wachstumskonstante" 

 {^^wahre WachstumsgeschwindigkeW^ x time). 



Schmalhausen gives no explanation of the breaks in the cases of those organs which have 

 two values of Cvt, but calls attention to the fact that the organs of early differentiation 

 have low Cvt and vice versa. 



If the curve obtained by plotting Cv (Brody's k) against time is a regular hyperbola, 

 then the product Cvt should be 300. If it exceeds this figure, the curve is descending and 

 becoming asymptotic less rapidly, i.e. the rate of growth (instantaneous) is not falling off 

 as rapidly as it will be if the product is less than 300 at any given moment. 



This constant he calls the "Wachstumskonstante", and its values, 

 calculated by him for a number of embryonic processes, are seen in 

 Table 56. It is perhaps the least convincing part of his exposition, 

 for when during a certain series, e.g. the growth of the human 

 embryo, the constant Cvt oscillates between 899 and 93 as extreme 

 limits, one may legitimately doubt whether great stress can be laid 



* Brody himself does not find this to be so. 



