MEDULLA OF BONES. 145 



most external Haversian lamellae originate apparently by 

 centrifugal deposition, whilst the internal Haversian lamellae 

 originate in centripetal deposit. 



If sections are made of growing bones decalcified with 

 chromic acid, or if bone be macerated in Miiller's fluid, which 

 however does not facilitate their section, and are then rubbed 

 down with this fluid and treated with carmine, the osteoblastic 

 layers and the immediately adjacent youngest layer of bone 

 acquire an intensely red colour, whilst the remainder of the 

 osseous tissue, with the exception of the bone corpuscles, 

 remains uncoloured. We thus obtain specimens very similar to 

 those made from the bones of animals fed for a short time 

 with madder, which have been described and depicted by 

 Tomes and Hassall.* 



It is well known that it has been sought to draw some 

 definite conclusions respecting the process of absorption and 

 regeneration of bone, from the observation of the laminated 

 coloration of the osseous tissue occurring after the use of 

 madder, on the ground that such coloured parts represent the 

 most recently formed layers. 



It is well worthy of notice that the experiments with 

 madder first instituted by Du Hamel/f" and repeated at a later 

 period by Flourens,J at a time when very little was known 

 respecting the histological process of ossification, and which 

 were certainly unjustly brought into discredit by Gibson, 

 have again been recently taken up by Lieberkiihn. The above- 

 mentioned analogies, and the more delicate histological relations 

 occurring in the formation and resorption of osseous tissue, still 

 require to be subjected to a systematic investigation. 



CONTENTS OF THE BONE CAVITIES. 



The medulla which occupies the central cavity, and the large 

 medullary spaces especially found in the fully developed long 

 bones, is composed of a delicate connective tissue traversed by 



* Loc. cit., plate 30, fig. 6. 



t Memoires de VAcademie de Paris, 1742, p. 354 ; 1743, p. 138. 



J Annales des Sciences Naturelles, serie 2, xiii., p. 103. 



Meckels' Archiv, Band iv., p. 482. 



