68 THE RATE OF GROWTH [ch. 



marked differences between different races, as we shall presently 

 see there are between the two sexes, in regard to the epochs of 

 acceleration of growth, in other words, in the "phase" of the 

 curve. 



It is evident that, if we pleased, we might represent the rate 

 of change of acceleration on yet another curve, by constructing a 

 table of "second differences"; this would bring out certain very 

 interesting phenomena, which here however we must not stay to 

 discuss. 



Annual Increment of Weight in Man (kgm.). 

 (After Quetelet, Anihropometrie, p. 346*.) 



Increment Increment 



12-13 4-1 3-5 24-25 0-8 - 02 



The acceleration-curve for man's weight (Fig. 5), whether we 

 draw it from Quetelet's data, or from the British, American and 

 other statistics of later writers, is on the whole similar to that 

 which we deduce from the statistics of these latter writers in 

 regard to height or stature ; that is to say, it is not a curve which 

 continually descends, but it indicates a rate of growth which is 

 subject to important fluctuations at certain epochs of life. We see 

 that it begins at a high level, and falls continuously and rapidly f 



* The values given in this table are not in precise accord with those of the 

 Table on p. 63. The latter represent Quetelet's results arrived at iii 1835; the 

 former are the means of his determinations in 1835-40. 



f As Haller observed it to do in the chick (Elem. viii, p. 294): "Hoc iterum 

 incrementum miro ordine ita distribuitur, ut in principio incubationis maximum 

 est: inde perpetuo minuatur." 



