192 OSSEOUS SYSTEM, 



OF THE MEDULLARY SYSTEM OF THE BONES. 



Q. Is there a membrane, or what may be termed an in- 

 ternal periosteum, in the osseous cells. 



*ft. Bichat thinks not; but supposes the medulla to be 

 exhaled by a vascular net-work. 



Q. What part of the osseous medullary system possesses 

 animal sensibility? 



*#. That vital property is found only in the middle of 

 the long bones. The same part of the system possesses 

 extensibility and contractility of texture. 



Q. Where are the pains usually ascribed to the bones 

 themselves, really seated? 



/?. In the medullary texture in the middle of the long 

 bones. 



Q. How is the medullary system divided? 



A. .There is the medullary system of the ends of the 

 long bones; that of the short and flat; and that of the mid- 

 dle of the long bones. 



Q. In what interesting particular does the medullary 

 system of the middle of the long bones differ from the 

 others ? 



*#. In this, that the vital forces of that system are much 

 more active than in those of the short and flat bones, or 

 even in the ends of the long bones. 



Q. Is the marrow altered in diseases? 



A. In some chronic affections it becomes mucilaginous 

 or gelatinous, resembling in many respects foetal marrow 

 in which there is no fat. 



Q. What do you mean by internal necrosis? 



fl. The destruction of the medullary substance of the 



