METABOLISM IN DISEASES OF BONES AND JOINTS T43 



The results in the case of sulphur are of especial interest (Table 15). 



TABLE 15 



PERCENTAGE OF SULPHUR IN DRIED BONE 



The organic matrix of hone is made up largely of glycoproteins which, 

 compared with most other proteins, are rich in sulphur; so that in osteo- 

 malacia, a condition in which the percentage of organic matter is in- 

 creased, we should expect to find an increased amount of sulphur. But 

 if the process were a halisteresis, similar to that which takes place when 

 bone is subjected to the action of acid, we should expect, in cases like the 

 two cited by McCrudden, in which the calcium has decreased to nearly 

 half its normal value, to find the amount of sulphur, correspondingly, only 

 doubled, whereas in both cases it has increased nearly four-fold. This, 

 again, as in the case of magnesium, suggests that there is an apposition 

 of new tissue, in this case an apposition of tissue similar to the organic 

 matrix of normal bone. 



Less complete analyses are available for diseases other than osteo- 

 malacia. A two- to three-fold increase in the magnesium content of the 

 bone has been found in osteitis deformans. Thus Tourette and Mag- 

 delaine found the ratio of magnesium to calcium in the bone in this disease 

 11:1000; and Robin found it 18:1000. The ratio in normal bone is 

 5:1000 ( McCrudden (d)). In rickets Gassman found a twelve per cent 

 fall in the percentage of calcium in the bones, accompanied by an increase 

 of more than five hundred per cent in the magnesium content. Cattaneo 

 found a similar decrease in calcium and increase in magnesium. (Table 

 16.) 



TABLE 16 



CHANGE IN COMPOSITION OF BONES IN RICKETS 



To summarize the results of bone analyses: In osteomalacia the pro- 

 portion of inorganic constituents is decreased and the proportion of 

 organic constituents increased. The decrease in inorganic constituents is 

 due to a loss of calcium phosphate. The proportion of magnesium phos- 

 phate and of the organic matrix of the bone is increased. Th3 increase is 



