GROWTH AFTER INANITION FOR VARIOUS PERIODS. 33 



6. Skeleton (Table IV.). 



Three weighings were taken of the skeleton prepared as 

 described by Jackson ('15), who found that the skeleton increases 

 greatly in weight during maintenance. The high relative weight 

 of the ligamentous skeleton (17.2-19.8 per cent.) in my two rats 

 killed after nine weeks of maintenance as compared with Jackson's 

 normal at three weeks (15.7 per cent.) is in agreement with this 

 conclusion. 



On refeeding, the relative weight of the ligamentous skeleton 

 gradually decreases, reaching an average (in the females) of 12.4 

 per cent, at the end of the second week. This is slightly lower 

 than the percentage weight (14.0) obtained by Jackson and Low- 

 rey for the ligamentous skeleton in normal rats of about the same 

 body weight. It appears then that the skeleton had decreased 

 in relative weight during the first two weeks of refeeding suffi- 

 ciently to reach the normal proportions. In the rats refed four 

 weeks, and also in the adult test rats, the relative weights of the 

 ligamentous skeleton were practically normal as compared with 

 the controls. 



The data (Table IV.) show that a marked increase occurred 

 also in the moist cartilaginous skeleton in the test rats during 

 maintenance, as is evident upon comparison with the relative 

 weight (11.4 per cent.) given by Jackson ('15) for the normal rat 

 at three weeks. During refeeding, the relative weight of the 

 moist cartilaginous skeleton gradually decreased, reaching an 

 average of 11.9 per cent, of the body in the rats refed four weeks, 

 as compared with an average of 11.5 per cent, in the controls. 

 In the adult rats there was very little difference between the 

 test animals and controls. 



The dried cartilaginous skeleton was also relatively heavier in 

 the maintenance rats at twelve weeks (5.24-5.96 per cent.) than 

 the normal (3.43 per cent.) found by Jackson for rats at three 

 weeks of age. On refeeding, the relative weight of the dried 

 skeleton has decreased notably by the end of one week (Table 

 IV.), and has probably reached the normal at two weeks. After 

 four weeks' refeeding, and in the adults, the percentage of the 

 dry skeleton is nearly identical in test animals and controls. 



The relative amount of dry substance in the cartilaginous 



