70 CELL-DIVISION AND GROWTH II. 2 



weight. Quetelet's figures do not show the rise in rate about 

 the time of puberty, but this phenomenon is apparent in the 

 data furnished by Bowditch, Boas, and Roberts (see Fig. 42). 

 The change in the growth-rate is practically the same in women 

 as in men. As with weight, the rise of rate at the time of 

 puberty is earlier. 



The decline in the growth-rate of chest-girth is shown in the 

 same figure (Fig. 40). It will be noticed at once that in this case 

 the drop in the first year is very great indeed, from nearly 50 % to 

 nearly 5 %, and that the rate is only diminished by another 2-4 % 

 in the next nineteen years. The weight will depend upon the 

 volume and the volume on both stature and girth ; in fact 

 a rough weight-curve might be constructed from the measure- 

 ments of stature and girth. It is evident that the sudden loss 

 in the rate of total growth after the first year is due to the very 

 rapid decrease in the percentage increment of girth. 



It may be mentioned that other measurements of girth girth 

 by the sternum, the waist, the hips, the neck, the biceps, the 

 thigh show the same exceedingly abrupt decrease, almost to 

 the minimum rate, between the first and second years. 



In other cases distance between the eyes, width of mouth, 

 length of hand, length of foot, arm-length, leg-length, length 

 and breadth of head, distance from the crown of the head to 

 the first vertebra, length of the vertebral column the change 

 is more gradual ; the rate of change, however, differs in different 

 cases. As an instance of this let us consider the measurements 

 from the crown to the first vertebra, the length of the vertebral 

 column, and the leg-length which together make up the total 

 stature. The growth-curves of these three and of the whole 

 stature are presented in the figure (Fig. 41), from which it will be 

 seen that the growth of the leg is faster than that of the verte- 

 bral column (until the eighteenth year), and this than that of the 

 head. Increase in stature takes place at nearly the same rate as 

 that of the vertebral column, but is on the whole a little faster. 



There are few cases besides man in which we possess in- 

 formation as to the growth of the parts. In the sea-urchin, 

 Strongyloccnirotits, Vernon has shown that the growth-rate of the 

 oral and aboral arms of the Pluteus diminishes rapidly from 



