252 



HENRY H. DONALDSON 



gives the same information for the corresponding divisions of 

 both hind limbs at intervals of 0.05 gram. 2 



Chart 7 gives the smoothed graphs for the relative weights 

 of the three divisions of the fore limbs on the weight of the bones 

 of both fore limbs, and chart 8 the smoothed graphs for the cor- 

 responding divisions of the hind limbs on the weight of the bone 

 of both hind limbs. The outstanding relations shown by these 

 graphs are the similar behavior of the corresponding bones within 



ACE IN DAYS 



360 



Chart 6 Absolute weight of entire fresh skeleton on age — according to sex 

 (albino rat). Table 5. 

 • Males. A Females. 



each limb and the continued relative growth of the first two 

 segments of the limb as contrasted with the behavior of the most 

 distal segment, which in both cases diminishes in its relative 

 weight during all the later portion of the growth period — i.e., 

 after a limb bone weight of 0.22 gram for the fore limbs (table 6) 

 and 0.45 gram for the hind limbs (table 7). In the fore limb 



2 The sign (2) after any paired bone indicates that the value given in the 

 table applies to the two bones (right and left) taken together, although the 

 designation of the bone is in the singular number. 



