Ill] 



OF SEASONAL GROWTH 



233 



winter rates grow less and less. The fluctuation in rate represents 

 a vibration which is gradually dying out; the amplitude of the 

 sine-curve diminishes till it disappears; in short our phenomenon 

 is simply expressed by what is known as a "damped sine-curve*." 



Growth in height of German military cadets, in half-yearly periods 



Increment (em.) 



cm. 4 



years 



Fig. 68. Half-yearly increments of growth, in cadets of various ages. 

 From Daffner's data. 



The same thing occurs in man, though neither in his case nor in 

 that of the fish have we sufficient data for its complete illustration. 

 We can demonstrate the fact, however, by help of certain measure- 

 ments of the height of German cadets, measured at half-yearly 

 intervals t- In the accompanying diagram (Fig. 68) the half-yearly 

 increments are set forth from the above table, and it will be seen 



* The scales, on the other hand, make most of their growth during the int/er- 

 mediate seasons: and with this peculiarity, that a few broad zones are added to 

 the scale in spring, and a larger number of narrow circuli in autumn : see Contrib. 

 to Canadian Biology, iv, pp. 289-305, 1929; Ben Dawes, Growth... in plaice, 

 Journ. M.B.A. xvii, pp. 103-174, 1930. 



t From Daffner, Da^ Wachstum des Menschen^ p. 329, 1902. 



