ON THE STRUCTURE AND DEVELOPjVIENT OF BONE. 133 



ing fibres of which the lamellae are made up. A longitudinal 

 section of the bone presents a corresponding appearance, for as 

 the fibres run more or less obliquely to the axis of the bone, 

 they present cut ends in a longitudinal section also. It thus 

 appears that the animal basis of bone is made up of lamellae 

 composed of fine reticulating fibres. ..." It would seem, 

 therefore, that although Sharpey notes the existence of clear 

 zones alternating with the granular or fibrous zones, he does 

 not attach sufficient importance to them to reckon them as an 

 integral part of the lamella. 



Eanvier' describes a section of hard bone as showing " deux 

 especes de lamelles qui alternent I'une avec I'autre pour former 

 les couches successives ; les unes homogenes . . . les autres 

 d^aspect strie. ... II est facile de se convaincre que I'aspect 

 strie d'une des especes de lamelles est du a de petits ponts a 

 bords sinueux, formes d'une matiere semblable a celle des 

 lamelles homogenes. 



"Cette structure des lamelles osseuses se voit aussi bien sur des 

 coupes longitudinales que sur des coupes transversales.^ . . . " 



It is clear that this represents little more than a reproduc- 

 tion of Sharpey's original description. The facts are the same, 

 but the deduction as to what constitutes an osseous lamella is 

 difl'erent, and there would obviously be in a given thickness, 

 according to Ranvier, twice as many lamellae as would be 

 enumerated by Sharpey. 



In order to arrive at a more exact definition of a lamella, it is 

 necessary to compare the structure of bone with that of the 

 other lamellated tissues to which it is most closely allied in 

 essential structure, especially some of the forms of connective 

 tissue. Of these that composing the cornea affords the most 

 striking analogy in structure to osseous tissue. Thus, the cornea 

 is composed of a number of lamellae which can be separated 

 from one another, and which are made up of fibrillated bundles 

 united together in the same lamella by a homogeneous ground 

 substance which also serves to bind together adjacent lamellae. 

 This interlamellar ground substance is partially occupied by the 



' ' Traiti Technique,' p. 314. 



2 Ranvier goes on : " Cela prouve que la striation est reellement produit 

 par des petits ponts, et non pas par des lames longitudinales, com me on 

 pourrait le croire si I'aspect stri6 ne se montrait que sur des coupes trans- 

 versales." Is not Sharpey's explanation, that the fact of the same appear- 

 ance being seen whether the section be transverse or longitudinal is owing 

 to the oblique direction of the intercrossing fibres, a far more reasonable 

 one? But M. Ranvier cannot admit the existence of such fibres : "Nous 

 avons essaye le proc^de indique par I'auteur (Sharpey), mais nous n'avons 

 pas reussi a voir la texture fibreuse dont il parle !" 



