134 INANITION AND MALNUTRITION 



visional calcification, and an intensified vascular invasion from the marrow 

 and perichondrium. A characteristic, irregular "metaphysis" zone is thereby- 

 produced, composed of excessive osteoid substance (uncalcified bone), which 

 replaces the cartilage, apparently by metaplasia. Subperiosteal osteoid is 

 also formed. The bone marrow becomes atrophic and variably fibroid in 

 character. Cessation of osteogenesis, together with continued absorption 

 in the spongiosa and cortical bone, may produce a variable degree of osteo- 

 porosis. Recovery is possible upon appropriate diet, but severe rickets causes 

 permanent dwarfing and deformity. In late or adult rickets (osteomalacia) 

 there is much decalcification of bone (halisteresis), and the enchondral ossi- 

 fication changes are absent. 



Scurvy, caused by lack of vitamin C, is characterized by a general hemor- 

 rhagic tendency, inhibited osteogenesis and marked atrophy of the osseous tissue. 

 The skeleton is fragile and brittle, with a histological structure quite different 

 from that in rickets. In the young (infantile scurvy or Barlow's disease), 

 the proliferative cartilage zone is widened, as in rickets, but the provisional 

 calcification takes place. The normal invasion and replacement of this carti- 

 lage by osteogenic marrow tissue fails to occur, however, and the accumulation 

 of calcified trabeculae forms a wide, weakened zone, which easily fractures, 

 causing hemorrhages and an irregular swollen area ("Triimmerfeld"). The 

 adjacent marrow undergoes a fibroid degeneration, related to that in rickets and 

 other forms of inanition, but with characteristic multiple hemorrhages. Atrophy 

 of the osteogenic tissue, together with continued absorption in both spongiosa 

 and cortex, results in osteoporosis which is more constant and pronounced than 

 in rickets. Except in the most extreme stages, recovery is possible upon appro- 

 priate diet. 



Fetal scurvy is produced when pregnant guinea pigs are placed upon scor- 

 butic diet, but the occurrence of fetal rickets is doubtful. There are marked 

 differences among species in the susceptibility to scurvy and rickets, as found 

 also in other dietary deficiencies. 



Aqueous inanition, with dry diets, occasions skeletal changes apparently 

 similar to those found in total inanition. This is probably due in part to the 

 lessened food-intake on dry diets. 



(A) Effects of Total Inanition, or on Water Only 



Weight Changes in Adults. — Actual weights of the skeleton in mammals 

 subjected to various degrees of inanition, in comparison with those of normal 

 controls, indicate little or no loss, according to observations on pigeons by 

 Chossat ('43) and Lukjanow ('89); on the cat by Bidder and Schmidt ('52); 

 on dogs by Falck ('54, '75) and Schondorff ('97); on hibernating marmots by 

 Valentin ('57); on various mammals by Bourgeois ('70), C. Voit ('66, '94), 

 and E. Voit ('05a); on rabbits by Gusmitta ('93), Pfeiffer ('87), Weiske ('97) 

 and Sedlmair ('99); on the femur of guinea pigs by Lazareff ('95); on albino 

 rats by Jackson ('15); and on man according to Rokitansky ('54) and Cohnheim 

 ('89). Where apparent loss in weight of the skeleton occurs, it is almost always 



