34 CHESTER A. STEWART. 



skeleton had also increased from 31.4 per cent. (Jackson, '15) 

 for the normal three weeks' rat, to an average of 34.5 per cent. 

 in the rats killed after nine weeks of maintenance. In the rats 

 refed four weeks the dry substance increased to 45.9 per cent, of 

 the moist cartilaginous skeleton, which is fairly close to that 

 found in the control (46.6 per cent.). 



It therefore appears that the ligamentous and cartilaginous 

 skeletons reach the normal proportions during the first two 

 weeks of refeeding. This is probably true also for the dry skele- 

 ton, although controls are lacking before the fourth week. 



7. Musculature (Table IV.}. 



In the two rats killed at the end of nine weeks of maintenance 

 the relative weight of the musculature (36.2-38.3 per cent.) is 

 considerably higher than the norm (31.2 per cent.) obtained by 

 Jackson ('15) for the three weeks' rat. This may be due partly 

 to an increase in the musculature during maintenance (a slight 

 increase being found by Jackson). The body weight is above 

 normal in these two rats, however, in which case the musculature 

 would normally be relatively .heavier. For the normal rat at 

 42.4 grams, Jackson found the musculature forming 35.3 per 

 cent., although at 64.4 grams body weight Jackson and Lowrey 

 ('12) found the musculature forming 32.7 per cent. 



In my test rats refed one half week (average net weight 40.7 

 grams) the musculature averaged 34.3 per cent., whereas in the 

 female rats refed two weeks (average net weight 69.4 grams) 

 the musculature formed only 32.1 per cent, of the body. There 

 is evidently considerable individual variation, and it is difficult 

 to make the dissection of the musculature in a uniform manner. 

 In the rats refed four weeks, and also in the adult test animals 

 the percentage weight of the musculature was nearly identical 

 with that of the controls. 



From the foregoing it may be concluded that the musculature 

 (which possibly was slightly heavier than the normal for body 

 weight at the end of maintenance), assumed practically the 

 normal proportions during the first week of refeeding and re- 

 mained normal at all subsequent periods. 



