EFFECTS ON THE SKELETON 1 35 



less than 10 per cent, usually below 5 per cent, which is very slight in comparison 

 with the corresponding loss in body weight. 



The nearly stationary weight of the skeleton during starvation, despite the 

 loss of calcium phosphate and marrow fat, is possible because the substances 

 lost are largely replaced by water, the specific gravity of which is higher than 

 that of the fat (cf. Wellman '08, Jackson '15, Lusk '17). 



In the skeleton of amphibia, however, the destructive effect of starvation may 

 be much greater. Harms ('09), Kammerer ('12) and Nussbaum ('14) found in 

 fasting Triton and Proteus a marked shrinkage in the length of the vertebral 

 column, but no weights of the skeleton were recorded. Ott ('24) found that 

 during hibernation and subsequent inanition in the leopard frog (Rana pipiens), 

 the ligamentous skeleton in general showed no loss in weight, but rather a 

 slight increase (Table 6). In the group with loss of 60 per cent in body weight, 

 however, there was an apparent decrease of 12 per cent in the weight of the 

 skeleton. There was a marked and progressive decrease in dry substance. 



Weight Changes in the Young. — The earlier observations upon the skeleton 

 in malnourished young children by Bouchaud ('64), Ohlmuller ('82) and Herter 

 ('08) indicated merely that the skeleton, though retarded in growth, fails to 

 lose in weight and (as in adults) becomes relatively heavier in proportion to 

 body weight. Later it became apparent, as already stated in Chapter IV, that 

 in young individuals subjected to underfeeding, certain dystrophic growth 

 changes may occur, chief among which is a persistent growth of the skeleton. 

 This, was observed by Camerer ('05), Variot ('07a, etc.), Stolte ('13), Jackson 

 ('22), and others in the human infant; by Waters ('08), Falke ('10), Trowbridge, 

 Moulton and Haigh ('18, '19) and Moulton, Trowbridge and Haigh ('21) in 

 calves; by Aron ('10, 'n, '13) in puppies and rats; by Jackson ('15a), Jackson 

 and Stewart ('18), Barry ('20, '21) and Stewart ('16a, '18, '19) in the albino rat 

 (see p. 89; Table 4); by Thompson and Mendel ('18) in the mouse; and by 

 Podhradsky ('23) in young fasting tadpoles of Rana jusca. Further data upon 

 the weight of the ligamentous skeleton in atrophic infants are given in Table 3. 



That such dystrophic skeletal growth does not invariably occur in mal- 

 nourished young, however, is indicated by the observations of Tschirwinsky 

 ('10) on lambs, and by Lascoux ('08), Freund ('09), Lesage ('11), Waser ('20) 

 and others on atrophic children, as mentioned in Chapter IV. The skeletal 

 growth is doubtless affected by the amount and character of the insufficient diet, 

 and apparently varies also according to age (Birk 'n; Lust '13). The age 

 factor appears most clearly in the work of Jackson, Stewart and Barry (Table 4), 

 which indicates that in the albino rat the persistent growth tendency of the 

 skeleton in undernourished rats is relatively strongest after the weaning period 

 (3 weeks of age), being less in older as well as in younger stages; and not evident 

 in the fetus. 



Structural Changes in the Adult Bone. — Various observers have noted that 

 the bones tend to become weakened and brittle during conditions of prolonged 

 inanition (cf. v. Recklinghausen '10), but in most cases it appears probable that 

 these changes are primarily due to certain specific (especially mineral) defi- 

 ciencies, which will be mentioned later. This applies especially to the various 



