338 SPECIAL HISTOLOGY. 



present distinct ramifications and free terminations of the 

 primitive fibrils. A nerve of 0-03"', which together with an 

 artery entered the fibrous external part of the symphysis pubis, 

 may here be mentioned. With regard to the cartilages, I have 

 as yet noticed only in the cartilage-canals in the septum 

 narium of the Calf, together with vessels (arteries), very dis- 

 tinct, fine nervous twigs, measuring 0-006 — 0-01'", with fibres 

 of 0-0012 — 0-0016'" thick. In the articular capsules nume- 

 rous nerves exist, although they belong principally to the 

 so-called fibrous capsules, and to the loose connective tissue 

 external to the synovial membrane. In the knee I have seen 

 nerves, even in the true synovial membrane, although in 

 general they are rare, and are most distinct in the large 

 vascular processes, which besides arteries, contain nerves of 

 0-007 — 0-008'", with fine, also dividing filaments of 0-0008 — 

 0-002'". I have also seen in the synovial membrane itself, 

 close to the condyles of the femur, tolerably numerous nerves 

 composed of delicate fibres. 



§ 100. 



Development of the Bones. — In respect of their development, 

 the bones fall into two groups, viz. into those which are pre- 

 formed in a cartilaginous state (primary bones), and into those 

 which from a small beginning are developed in a soft blastema 

 (secondary bones) . The former, while yet in the cartilaginous 

 condition, present all their essential parts (diaphvses and 

 apophyses, body, arches and processes, &c), and as far as 

 their cartilaginous basis is concerned, originate like other 

 cartilages, and continue to grow r more or less in the same 

 manner. They afterwards become ossified (in man, all of 

 them) from within to without, transforming a portion of the 

 cartilage completely into bone, so that what was the peri- 

 chondrium becomes the periosteum, and afterwards attaining 

 their ultimate figure, partly by means of the remaining car- 

 tilage, which continuing to grow with them is successively- 

 ossified, and partly by means of a soft, ossifying blastema, 

 which is deposited layer upon layer on the inner surface of 

 the periosteum. In the second group, the bone is formed 

 from a very limited, soft, non-cartilaginous basis, and con- 

 tinues to grow at the expense of that substance, which is 



