REMARKS 



OSSEOUS, CARTILAGINOUS, AND LIGAMENTOUS STRUCTURES. 



The bones are the solid framework which 

 gives stability to the whole fabric, and af- 

 ford fixed bearings upon which the powers 

 regulating the varied movements operate. 

 The bones, then, are considered as the most 

 dense and solid structures of the animal 

 frame : affording support, and in many parts 

 protection, .to some of the softer parts ; at 

 the same time, the leverage which regulates 

 the action of a limb is derived from the 

 osseous structure. 



On making an examination of a bone, 

 we find that its external surface is the hard- 

 est part, and it differs very much in thick- 

 ness in different bones, and in different 

 animals. The long bones (or cylindrical) 

 of the horse contain less marrow, and are 

 more cancellated within, than the bones of 

 the human subject : in many of the former 

 the whole arena is ©ccupied by cancelli. 

 The bones of the ribs have an osseous plat- 

 ing differing in thickness in various sub- 

 jects, and within is a cellular structure which 

 may be termed diploe. 



The marrow, as it is termed, is a soft 

 substance of an oleaginous character, con- 

 tained in an infinite number of sacs, depos- 

 ited and suspended in the cavities of bones 

 and in the cancelli. The marrow sacs are 

 composed of a delicate vascular membrane, 

 which isolates them from each other, and 

 prevents the marrow from gravitating or 

 passing into the osseous structure. 



Bones present the appearance of lamella, 

 yet they are fibrous ; the fibres of the cylin- 

 drical bones are longitudinal; in the flat 

 bones they have a radiated appearance, and 

 in the short and peculiar shaped bones, the 



fibrous arrangement is more irregular and 

 difficult to trace. 



The basis of the osseous structure is 

 nearly the same as the membranous parts,* 

 being composed of fibrous lamina? or plates, 

 which are connected together so as to form, 

 by their intersection, a series of cells anal- 

 agous to those of the cellnlar structure. 

 This theory has been disputed by some 

 distinguished physiologists ; the moderns 

 contend that the osseous fabric is cellular.f 



Bones are invested, on their exterior, ex- 

 cept those parts plated with cartilage, with 

 a membrane termed periosteum. Through 

 this medium an arterial and venous com- 



* " The analysis of a bone into its two constituent parts 

 is easily effected by the agency either of acids or of heat. 

 By macerating a full-grown bone for a sufficient time in 

 diluted muriatic acid, the earthy portion of the bone, 

 amounting to nearly one-third of its weight, is dissolved 

 by the acid ; the animal poition only remaining. This 

 animal basis retains the bulk and shape of the original 

 bone, but is soft, flexible, and elastic ; possessing, in a 

 word, all the properties of membranous parts, and corres- 

 ponding in its chemical character to condensed albumen. 

 A portion of this solid animal substance aff"ords gelatin by 

 long boiling in water, especially under the pressure, ad- 

 mitting of a high temperature, to which it may be sub- 

 jected in Papin's digester. On the other hand, by sub- 

 jecting a bone to the action of fire, the animal part alone 

 will be consumed, and the earth left untouched, preserv- 

 ing, as before, the form of the bone, but having lost the 

 material which united the particles, presenting a fragile 

 mass which easily crumbles into powder. This earthy 

 basis, when chemically examined, is found to consist prin- 

 cipally of phosphate of lime, which composes eighty-two 

 hundredths of its weight ; and to contain also, according 

 to Berzelius, minute portions of fluate and carbonate of 

 lime, together with the phosphates of magnesia and of 

 soda." — Roget. 



t The best authority in support of the cellular theory is 

 Scarpa. Percivall advocates the laminated and fibrous 

 theories. 



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