OSTEOMALACIA 443 



iron.-" Ilofmeister advances the hypothesis that when the cartilage 

 or other matrix becomes saturated with calcium salts, any decrease 

 in COo content of the solution will lead to a precipitation of calcium 

 salts, thus restoriiijj; to the cartilage its power of absorbing more 

 calcium salts whenever the fluid comes to it with a higher degree of 

 saturation with calcium salts and COg. This hypothesis is in har- 

 mony with Barille's observation that when the CO2 is reduced the 

 complex car])oii-pliosphate of calcium precipitates a mixture of car- 

 bonate and phosphate in the same proportions as found in bones and 

 calcific deposits generality. The fact that this ratio (10 to 15 per 

 cent. CaCO.j and 85 to 90 per cent. Ca;j(P04)o), is found in all stages 

 of calcification, is entirely in favor of the above hypothesis, and 

 opposed to the idea that any special chemical precipitant formed in 

 the calcifying area is responsible for the deposition of calcium. 

 Taken all in all, the evidence seems in favor of the view that normal 

 ossification and pathological calcification (except metastatic calcifica- 

 tion and the calcification of fat necrosis and other areas of necrotic fat 

 tissue) depend more upon physico-chemical factors and variations in 

 CO2 concentration than upon the presence of chemical precipitants 

 in the tissues. 



OSTEOMALACIA 27 



In this condition the quantity of inorganic salts in the bone is 

 greatly decreased, while, at the same time, their place is taken in 

 part by new-formed osteoid tissue ; as a result, the proportion of the 

 weight of the bone formed by inorganic salts is reduced to as low as 

 20 to 40 per cent., instead of being from 56 to 60 per cent., as in nor- 

 mal bone. This has suggested that the cause of the disease may be 

 a solution of the lime salts by some acid, but Levy -^ found that 

 in osteomalacia the proportion of calcium carbonate and phosphate 

 in the bones remains constant, as also does the proportion of cal- 

 cium and phosphoric acid ; if the decalcification occurred through 

 solution by lactic or other acids, the carbonate should be decora- 

 posed first, whereas the lime salts seem to be taken out as mole- 

 cules of calcium carbonate-phosphate ; i. e., in the same propor- 

 tion as they exist in the bone. On the other hand, it has been found 

 in Pawlow's laboratory that dogs kept for long periods after a pan- 

 creatic fistula has been established, develop a condition resembling 

 osteomalacia, "° which would seem most reasonably explained as due 

 to the constant loss of alkali in the pancreatic juice. Furthermore, 

 investigation of Levy's objection to the acid solution theory has led 



26 See Sprunt, Joiir. Exp. Med., 1011 (14), i^O. 



27 See also review in Albn and Neuberp's "^rineralstofTwechsel," Berlin, lfl06, 

 pp. 124-127; biblioirraphy by Zesas, Cent. Crenz. :\led. u. C'hir., 1007 (10), 801; 

 full discussion bv ]\IcCru'dde'n, Arch. Int. INIed., 1010 (•>), riW: 1012 (0), 27.3. 



28Zeit.. physiol. Chem., 1804 (10), 2.30. 



29 Babkin, Zeit. Stoffwechsel, 1010 (11), .561; Looser, Verh. Dent. Path. Gesell., 

 1007 (11), 201. 



