24 OSSEOUS TISSUE. 



A very important question forces itself upon our notice in con- 

 sidering the diseases of the bones, namely, whether there are con- 

 stant changes in the relative proportions of the mineral constituents, 

 and especially whether, when there is resorption of the bone-earth, 

 the strongly basic phosphate of lime is replaced by a less basic 

 salt. Unfortunately most of our analyses of morbid bones are not 

 of such a nature as to enable us to elicit from them even a probable 

 answer to this question. How seldom, after the bones have been 

 properly prepared for analysis, has it been attempted to ascertain 

 the quantity of carbonate of lime in the fresh bone, or in the earthy 

 constituents, by the direct determination of the carbonic acid ! 

 Indeed, in most analyses, the older method of Berzelius for the 

 determination of the phosphate of lime has been employed, accord- 

 ing to which we could never be certain whether we were weighing 

 8CaO. 3PO 5 or 3CaO.PO 5 . We shall presently notice the reasons 

 why this and similar questions are not so easy to answer as might 

 at first sight be supposed. It appears, from the analyses in our 

 possession, as if the carbonate of lirne first diminished and sub- 

 sequently again increased in a corresponding proportion with the 

 phosphate, in diseases of the bones ; it is only in osteophytes and 

 new formations of bone that we frequently find the carbonate of 

 lime exceeding the normal standard. 



After the preceding observations, it would scarcely seem neces- 

 sary to consider the composition of the bones in reference to the 

 ordinary nosological classifications ; we must, however, attempt this 

 course, partly to show how deficient our knowledge on this subject 

 is, when we cease to be contented with abstract diagnoses or mere 

 nominal designations, and attempt a more scientific mode of con- 

 sideration, and partly also to demonstrate that unless we implicitly 

 follow the leading maxims afforded to us by pathology, little real 

 advance can be made in this department. 



If we follow the method of inquiry at present pursued in patho- 

 logy, which refers almost all anatomical changes of the tissues and 

 organs to a so-called inflammatory process, we must begin by 

 studying the chemical changes which are coincident with the tex- 

 tural alterations of the bones that are induced by an ostitis, a perios- 

 titis, disease of the medulla, &c. But when we see the results of 

 an ostitis exhibiting themselves in various ways, according as it 

 depends on purely local causes or on specific or general diseases, or as 

 it attacks this or that group of bones, we may at all events conclude, 

 a priori, that even where the textural changes are nearly the same, 

 the chemical constitution of the altered bones need not be similar 



