444 



CALCIFICATION, COXCRETIOXS, AXD INCRUSTATIONS 



to the observation that when mixtures of calcium carbonate and phos- 

 phate are in colloids they are dissolved at equal rates.-''^ McCrudden 

 found tliat in the bones in human osteomalacia, together with the de- 

 crease in calcium there is an increase in the magnesium ^° and sul- 

 phur, because of newly deposited tissue poor in calcium. Histologic- 

 ally, absorption seems to depend largely upon a direct eating out of 

 bone tissue, both organic and inorganic substance, by osteoclasts 

 (Cohnheim), followed by a formation of an uncalcified osteoid tis- 

 sue. (Senile osteoporosis differs chiefly in that no new osteoid tissue 

 is formed.) According to Dibbelt ^^ when osteomalacia is experimen- 

 tally induced in pregnant dogs and then recovery is allowed to take 

 place, the decalcified bone substance present in the active stage does 

 not become calcified, but is absorbed and replaced by new bone. 



Studies of metabolism in osteomalacia have shown a loss of calcium 

 by the body, especially in the urine, as shown by the following table 

 given by Goldthw^ait et al. : ^' 



McCrudden also found a considerable retention of nitrogen and 

 sulphur, which may be retained in the new-formed osteoid tissue ; 

 magnesium is also retained, probably being substituted for calcium 

 in the bones. It is known that when magnesium and strontium are 

 given to growing animals they will partially replace the calcium in 

 the bones,^-'' while it is said by Etienne ^^ that excessive feeding of cal- 

 cium itself leads in time to decalcification of the bones. Zuntz ^* 

 found the respiratoiy metabolism in osteomalacia, within normal lim- 

 its, but tending to be low; protein metabolism shows nothing strik- 

 ing, but there is a high excretion of phosphoric acid througli the feces. 



Castration of women with osteomalacia has been frequently, but 

 not always, followed by improvement or recovery,^^"^ and Neumann, 

 and also Coldthwait, have found that in these cases the calcium loss is 

 rejjlaced by a marked calcium retention after the 0])eration. AVhat 

 tlie relation of the ovaries to calcium metabolism or to osteomalacia 



2naKran/. and Lioso<,'anfr, Dent. Monat. Zalniheilk., 1914, p. 62S. 



30 Corrolmratod by C'ai)pez/.U(>li, Biocliem. Zeit., 1909 (16). 355. 



31 Arbeit. Patli. Tnst. Tuhinf,'en, 1911 (7), 559. 



32Goldlli\vait, Painter, Osfjood and I\IcCr\idden, Amcr. .lour. I'livsiol.. 1905 

 (14), 389. 

 32a See Lelinerdt, Zeit. exp. Med., 1<)1;5 (1). 175. 

 33 Jour. I'livsiol. et Path., 1912 (14). lOS. 

 34Areli. f. fiyn., 1913 (99), 145. 

 34a Bibliography by Schnell, Zeit. Oeb. u. (Jyn., 1913 (75), 178. 



