GROWTH OF THE SKELETON 



285 



Table 25 gives, however, not the values for the weights of a 

 running millimeter, but the ratios of the square roots of these 

 values. The square roots stand to one another as do the trans- 

 verse diameters of the respective cylindrical segments 1 mm. in 

 length, and it is the ratio of these transverse diameters (the 

 value at 5 grams being taken as unity) which is required for 

 comparison with the corresponding ratios of the bone lengths at 

 the same phases of growth. 



TABLE 25 



Giving the ratios of the square roots of the values for the fresh xveights of a running 

 millimeter of the several long bones. These values are proportional to those for 

 the diameters of the hypothetical cylinders. Based on the division of the fresh 

 bone iceighls (table 12) by the fresh bone lengths (table 20) 



TABLE 26 

 Giving the ratios of the lengths of the several fresh bones. Based on data in table 20 



If tables 25 and 26 are examined with care it will be seen that 

 in a general way about one-half the total increase in diameter and 

 two-fifths of the increase in length has occurred at a body weight 

 of 20 grams (weaning time) and two-thirds of the total increase in 

 both diameter and length at a body weight of 100 grams (puberty). 

 As the ratios in tables 25 and 26 show, the growth in length is 

 proceeding more rapidly than the growth in the computed diame- 

 ter. This of course is a continuation of a change in shape, which 



