OSSEOUS TISSUE. 321 





CHAPTER VII. 



OSSEOUS TISSUE, AND THE BONES. 



OSSEOUS tissue is peculiar to the bones and teeth, and will be 

 first described ; after which the structure of the bones, consisting 

 as they do of the osseous and several other tissues blended together, 

 will be specified. 



SECTION I. 



OSSEOUS TISSUE. 



To the naked eye the bones present two forms of the osseous 

 tissue viz., the compact, and the cancellated or spongy. But, how- 

 ever important these distinctions are in a practical point of view, 

 microscopic examination shows them to be essentially identical, as 

 will be seen. 



The ultimate histological element of the osseous tissue is a pale, 

 oval, oblong, or angular granule, g^ UTJ of an inch in diameter. 1 

 (Kolliker.) These granules (Fig. 211) are blended 

 together so as to form membraniform expansions of Fig. 211. 

 varying thickness (the lamellae), or irregular masses 

 inclosing cavities of a peculiar form (the lacunae and 

 pores); and from the different conformations and ar- 

 rangements of these lamellae and masses, result the 

 compact and the cancellated bone-substance already ultimate grannies 



n of bone, isolated. 



mentioned. and in small mass . 



The thinnest lamellae or a simple plate of bone is es ; from the femur - 



. ,,. . c ' i -Magnified 320 di- 



formed by the apposition at their margins of a single ameters. (Tomes.) 

 stratum of granules. It must be remembered, how- 

 ever, that the osseous tissue is not always granular. It is sometimes 

 a perfectly clear hyaline substance. This form appears to be a more 

 recent and less perfect development than the granular ; and both 

 often appear in the same bone, and even in the same lamella of an 



1 ssW to T4&SO of an inch - (Todd and Bowman) One-sixth to one fifth the 

 diameter of the blood-corpuscles. (Tomes.) 



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