118 C. M. JACKSON AND C. A. STEWART 



weight, but it would seem that the relative plumpness of the 

 body (above referred to) is not due to accumulation of subcu- 

 taneous fat. 



Skeleton. The 'ligamentous skeleton' includes the bones, car- 

 tilages, periosteum, and ligaments. The fibrous structures were 

 removed by maceration (see earlier papers for technique) , leaving 

 the 'cartilaginous skeleton,' which was oven-dried to constant 

 weight as the 'dry skeleton.' 



A remarkably persistent overgrowth of the skeleton in general 

 has been observed during underfeeding in calves (Waters, '08) , 

 puppies (Aron, '11) and rats (Jackson, '15). Increase in body 

 length, indicating continued increase in skeletal growth, with 

 retardation in body weight, has also been noted in malnourished 

 human infants and children (Variot, '07; Freund, '09; Birk, '11; 

 Hess, '16). In rats underfed from birth, Stewart ('18) found at 

 three to ten weeks an excess weight of 19 to 24 per cent in the 

 ligamentous skeleton, 33 to 94 per cent in the cartilaginous skele- 

 ton, and 46 to 166 per cent in the dry skeleton. In such rats, 

 on ample refeeding to 25 to 75 grams in body weight, Jackson 

 and Stewart ('19) found that in general the skeletal weight has 

 dropped to normal proportions, or even subnormal (cartilagi- 

 nous and dry skeleton) , suggesting that although skeletal growth 

 persists during early inanition periods, its later growth may be 

 inhibited. The present data (table 2) tend to confirm this in 

 the test rats amply refed to maximum body weight. While 

 the condition in the last group is more uncertain (due to lack of 

 direct controls, as previously explained) the other groups show 

 uniformly subnormal skeletal weight. While small in the liga- 

 mentous skeleton ( — 2.4 to —11.9 per cent), it is more definite 

 in the cartilaginous skeleton ( — 7.0 to 24.7— per cent), which 

 probably accounts for the slightly subnormal body length. A few 

 observations on the weight of the dry skeleton (not given in the 

 table) show a slight deficit in the test rats, but they are too few 

 to be conclusive. 



Musculature. In rats underfed from birth to three, six, or 

 ten weeks of age, Stewart ('18) found the musculature slightly (8 

 to 12 per cent) above normal weight. In such rats, on ample 



