206 OSSEOUS SYSTEM. [sect. 107. 



year. The junction of most of the epiphyses and processes 

 with the diaphyses, takes place partly at the time of puberty, 

 partly towards the end of the period of growth. 



§ 107. The vital phenomena exhibited in the fully mature hones 

 are not, during the vigorous period of life, accompanied with any 

 notable or energetic morphological changes. It is true, that 

 some of the processes formerly considered, still extend into 

 this period — as the enlargement of the sinuses of the cranial 

 bones, the widening or deepening of the muscular and tendinous 

 impressions, and of the furrows of the vessels, etc. ; but we never 

 find any extensive new formation of bone under the periosteum 

 or in the Haversian canals, and an absorption on a considerable 

 scale going hand-in-hand with it. It was, indeed, believed for- 

 merly, that the colouring of the bones of the adult by the red 

 colouring matter of madder, proves that depositions of osseous 

 substance occur also at this period, because it was assumed, that 

 only the newly forming osseous tissue became coloured ; but since 

 it has been shown, that fully developed bones are rendered red by 

 madder, and that coloured bones of the adult do not become 

 decolorised (Bridle and Hugueny), the above-mentioned view can 

 no longer be maintained. Whether in the fully developed bone 

 a change, if not of the structural elements, at least of the atoms 

 occurs, the former remaining the same, is another question, for 

 the solving of which, hovever, the microscope furnishes no data. 

 So much is certain, that the organisation of the bones is of such a 

 kind, that notwithstanding their rigid nature, they- come on all 

 all sides, and most intimately in contact with the nutrient plasma 

 of the blood. Everywhere, in fact, where the osseous substance 

 is in connection with vessels, therefore, on the outer surface, upon 

 the walls of medullary cavities and spaces, and upon those of the 

 Haversian canals, there exist millions of fine openings crowded 

 closely together. These conduct the blood-plasma by means of 

 the canaliculi, into the bone-cells lying nearest to the above- 

 mentioned surfaces, from which it is then conveyed by other 

 canaliculi to more remote lacunas, and at length to the outermost 

 layers of the Haversian lamellae and the layers of the great 

 lamellar systems furthest removed from the vessels. "When the 

 immense number of the canaliculi and their numerous anastomoses 

 are considered, it must be confessed, that in no tissue of the human 

 body is better provision made for the distribution of the blood- 

 plasma, but, indeed, in almost no tissue is the supply of fluid to the 



