In the stabilized stage of
exostosis calcium exchange differs little from that of a normal individual whether the abnormal subject is maintained upon a
calcium-poor diet or upon one rich in this
element. In the progressive stage of the disease
calcium metabolism is markedly different from the normal in that
calcium is lost from the body in large amounts when the subject is maintained upon a
calcium-poor diet. This excessive elimination of
calcium is by way of both the urine and feces in a normal ratio. When placed upon a
calcium-rich diet
calcium is retained to an extent not widely deviating from that obtained in normal subjects. A resumption to a
calcium-poor diet again induces excessive
calcium elimination. In the stabilized stage of
exostosis magnesium excretion is two or three times greater than the intake whether the subject is maintained upon a diet poor or rich in
magnesium. In the progressive stage of the disease the general type of
magnesium excretion resembles that of the stabilized stage but the degree of elimination is not so marked.
Magnesium added to the diet in the stabilized stage is promptly excreted. The same test applied to the progressive stage gives evidence of retention of some
magnesium. The degree of retention, however, is much less than that shown by normal individuals. Absorption of both
calcium and
magnesium in
exostosis is not inferior to that of normal subjects. The facts enumerated suggest that in the early stages of
exostosis, that is during the proliferative cartilage changes, the progress of the disease may perhaps be checked by proper dietary procedure - restriction of
calcium and
magnesium intake.