OSTEO-POROSIS. 195 



ditions of soil and cultivation as indicated, the addition to 

 this natural diet of from one quarter to one half pound daily 

 of some nutritious material, as linseed cake, or a mixture of 

 linseed cake, oats, and bran, serves effectually to prevent the 

 occurrence of this diseased condition ; while, when such has 

 declared itself, a change to a better soil and a different 

 geological formation will, in combination with supplemented 

 food, materially hasten a restoration to robust health. 



"At one time it was believed, and many still hold to the 

 opinion, that the immediately operating cause in the production 

 of this diseased condition of bone was the presence of lime salts 

 in the soil, the result of the added alkali, and their transference 

 to and appropriation by the animal system, thus producing a 

 fragility of bone from excess of earthy constituents. Chemical 

 analysis of these bones has, however, disallowed this theory, 

 even if it were not untenable on other grounds. 



" It seems most probable that tliis condition of mal-nutrition is 

 rather to be regarded as resulting from certain changes which 

 the treatment of the soil has brought about, in the material 

 produced therefrom, and their unfitness when received into 

 the animal body for the elaboration of healthy tissue, than 

 from the passage in an unchanged form of any material already 

 existing in the soil into the component structures of the animal 

 body." 



In concluding this subject, I must give it as my own opinion 

 that the disease is due to development of the vascular and 

 fibrous structures of the bones, without a corresponding growth 

 of the true osseous and cartilaginous elements ; and in 

 support of this view I here quote from Eokitansky, who 

 says — " Osteo-porosis consists of the excessive development of 

 the tissues which occupy the canals and cells of the bones; 

 whilst at the same time the actual quantity of bony matter 

 remains unaltered." The growth of the contents of the canals 

 and cells must naturally cause a rarefaction of their walls, and 

 the bone becomes increased in volume, expanded, as the walls of 

 the expanding cavities become thinner and thinner, till at length 

 apertures are formed, and cavities which communicate one with 

 the other, containing a dark red medulla, traversed by dilated 

 vessels, and which sometimes become ruptured, and the cavities 

 become filled by loose or firm clots of blood. The fact that 



