122 THE CONNECTIVE TISSUES, BY A. ROLLETT. 



other classes of bones, when sections are carried through them 

 in various directions, except that the relations are simplified in 

 accordance with the smaller thickness here presented by the 

 compact substance. The lamellae again in these cases form 

 the extreme boundaries of the bone ; and if the thickness of 

 the compact substance is very small, they may even constitute 

 the entire mass of the bone. 



The trabeculae and lamellae of the cancellous tissue present 

 various forms, and in many instances the stronger trabeculae 

 are very regularly arranged, so that a kind of fibrillation is 

 exhibited, which pursues a definite direction in regard to the 

 surfaces of the bone examined. H. Meyer* has described 

 such appearances in the bones of the lower extremity of man, 

 and has shown that they stand in a certain relation to the 

 importance of the bone as an organ of support. In the stronger 

 trabeculae and lamellae of the cancellous tissue, Haversian 

 canals may be seen with their concentric lamellar systems. In 

 others we obtain, dependent on their more cylindrical or more 

 flattened form, and the side from which they are examined, 

 appearances similar to those offered by a flat view of the 

 lamellae of the compact substance ; or else striae and bands which 

 form the limits of the trabeculae in regard to the medullary 

 spaces they surround. 



We now turn to the consideration of the so-called bone 

 corpuscles and their processes. The form of these in the bones of 

 man is elongated and lenticular, and those of animals are for 

 the most part very similar. When seen on the broad surface 

 of the lamellae, they appear elliptical ; but seen on the small 

 transverse section of the lamellae, they resemble the trans- 

 verse section of a bi-concave lens. In reference to their 

 position to the lamellae, they are found at the margins of the 

 latter, arched in accordance with the curvature of the surface 

 of the lamellae where these form small arcs and adher- 

 ing to their convex surface. In regard to their number, 

 Welckerf counted in each square millimeter of the transverse 



* Reichert and Du Bois' Archiv, 1867, p. 615. 



t Zeitschriftfiir rationelle Medicin, N. F., Band viii., p. 232. 



