182 NON-INFLAMMATORY DISEASES OF BONES. 



and even under the periosteum. The bone itself is abundantly 

 supplied with vessels, and full of blood, and its colour is there- 

 fore darker than is natural, and red. Occasionally this change 

 reaches to such a degree that the cells of the spongy bones, 

 and those in the interior of the medullary tubes, become ex- 

 cessively distended, and, as their walls disappear, are merged 

 into larger cavities ; several cavities become single spacious 

 chambers, and the bones uncommonly soft and fragile. In the 

 second case the bone is, in addition, deprived of more or less 

 of its mineral constituents; and sometimes it is completely 

 reduced to its cartilaginous element, and appears like a bone 

 that has been steeped in acid. The bony corpuscles are empty, 

 and their rays have disappeared ; and when this is the case, the 

 lamellar structure is here and there obliterated. At other parts 

 the laniellae appear, as it were, to have fallen asunder, and the 

 corpuscles are seen quite distinctly interspersed between them. 

 It is upon this condition that the flexibility of rickety bones 

 depends." " It is remarkable," says Eokitansky, " that in cases of 

 general rickets the reduction of a bone to its cartilaginous 

 element so preponderates in some bones as to go on, even to 

 completion, without any trace of rarefaction." 



The late Professor Barlow taught that in rickets the car- 

 tilage yielded neither chondrine nor gelatine. This theory 

 was based upon one given in Simon's Animal Chemistry. 

 However, it is now ascertained that the analysed bones were 

 not rickety, but affected by mollities ossium. 



To conclude the subject of rickets, I must say that the 

 swelling of the articulations seems to indicate that the disease 

 does not consist in simple absence of the due quantity of 

 phosphate of lime, and analysis has proved that the cartilage 

 itself is altered in its constitution, the fat increased, and the 

 fluoride of calcium, present in healthy bone, is absent in rickets. 

 Analyses of some rickety bones give — animal matter 81-12, 

 earthy matter 18-88 in 100 parts; against animal matter 31-10, 

 earthy matter 68-90 in healthy bones. 



Allied to rickets is what I may describe as true atrophy of 

 the bones, or 



MOLLITIES OSSIUM, 



A remarkable case of which I have had the opportunity 



