266 



HENRY H. DONALDSON 



different diets, it has been thought proper to give the weight 

 values in all three conditions of moisture. Chart 12 gives the 

 smoothed graphs, for the fresh weights only. 



WEICHT IN CRAMS 



2.00 



1.75 

 150 

 1.25 

 1.00 

 .75 

 .50 

 .25 



UU 



EEH 



Growth of Skeleton— Albino Rat 

 Fresh 



BODY WEICHT IN CRAMS 



I I I I I I I I I I I I I I I I I I I III 



Chart 12 Absolute weight of the fresh limb bones, oh body weight (albino 

 rat). Table 12. 



X Femur, o Tibia plus fibula. • Humerus. A Ulna plus radius. 



PERCENTAGE OF WATER IN THE SKELETON AND ITS PARTS 



1. According to age 



As already stated, the skeleton has been dried in two stages, 

 first at room temperature (18°C. to 24°C, according to season) 

 for thirty days, and later in the water bath at 96°C. for six days. 

 It is generally recommended that for chemical analysis bones be 

 dried at 140°C, as this temperature drives off certain fractions of 

 water associated with the salts, but for our purpose this was not 

 deemed necessary, particularly as the reduction in weightjs only 

 about 1 per cent greater than that obtained by the method 

 employed. The percentages of water here given are therefore to be 

 interpreted in the light of the conditions under which they have 

 been obtained. The data for the percentage of water in the entire 

 skeleton after drying at 96°C. for six days, according to age, are 

 given under A in the left-hand portion of table 15, and the values 

 entered in chart 13. The percentage after oven drying was that 

 chosen for tabulation because it was assumed that it would be 



