OSSEOUS SYSTEM. 193 



bone, in which case the periosteum assumes the position 

 of nutritive parenchyma in which osseous matter is depo- 

 sited. 



Q. Is there in reality any marrow in the foetus? 



<fi. Beclard says there cannot be, because there is no 

 medullary membrane. 



Q. Have the medullary membrane, or the marrow any 

 agency in producing the synovia? 



Ji. They have not: for you may destroy the medullary 

 membrane, and still the formation of synovia continue 

 uninterrupted; again, the marrow is in greatest abundance 

 in those parts of the bone most remote from the synovia: 

 lastly, in children, where there is no marrow, synovia 

 abounds. 



Q. What is spina ventosa? 



*2. Beclard says it is a true cancer of the medullary 

 membrane. 



PATHOLOGY OP THE OSSEOUS TISSUE. 



Q. What are the diseases of the osseous tissue? 



#. Inflammation, caries, necrosis, exostosis, osteo-sar- 

 coma, fragility, and rachitis. 



Q. What gives peculiar aspect to the diseases of the 

 bones? 



A. The feebleness in their vital forces. 



Q. Give an example of healthy osseous inflammation ? 



ft. You, have it in the process of reuniting a fractured 

 bone. 



Q. What is caries ? 



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