GROWTH OF THE SKELETON 



279 



Examination of table 21 shows that the shrinkage is somewhat 

 greater in the humerus and femur than in the ulna and tibia and 

 that in passing from the room-dried to the oven-dried state the 

 shrinkage is about half that which is found in passing from the 

 fresh to the room-dried state. The absolute values of the cor- 

 rections called for are, however, very small, since in the instance 

 where the correction is greatest, it amounts to only 1 per cent 

 (femur — from fresh to oven-dried) and the maximum absolute 

 value corresponding to this is 0.4 mm., as can be seen by looking at 

 the last entry for the length of the fresh femur in table 20. 



TABLE 21 



Percentage losses in the length of long bones on drying. Mean values for rats above 



100 grams in body weight 



B. Lengths of bones on body length 



For a strict comparison, however, we should have the rela- 

 tions of these bone lengths to the body length of the rats. The 

 data are so given in table 22, which shows the absolute lengths 

 of the bones on body length. The smoothed graphs are in chart 

 18 and in chart 19, respectively. In table 23 the corresponding 

 relative values appear. 



In the case of each bone the last thirteen entries in table 23 

 after 160 mm. ( = 100 grams of body weight) are divided into 

 three subgroups and the averages of the relative bone lengths 

 on body lengths computed. For these subgroups we obtain the 

 values given in table 24. 



These data indicate a slight tendency for the humerus and 

 the femur to become relatively longer, while the ulna, radius, 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 26, NO. 2 



