THE OSSEOUS SYSTEM. 339 



continually developed anew, first at the margins only, but 

 afterwards also on the surfaces. When these bones have 

 attained a certain size, the blastema out of which they have 

 hitherto been developed may become, partially, cartilaginous, in 

 which ease the cartilage stands in the same relation to the 

 bone as it does in the former instance. The greatest part of their 

 formative substance, however, always remains in a soft con- 

 dition, and from it, without its ever becoming cartilaginous, 

 the principal bulk of the bone is produced. 



[Frequently as the development of the osseous tissue lias 

 already been discussed, still, in a general point of view, the 

 mode in which the bones, as organs, originate has hitherto been 

 little considered, and I believe that I Avas the first, in my 

 1 Zootomical Report/ Leipzig, 1849, to establish the principal 

 features of the process, and in my ' Microscopical Anatomy/ 

 II. 1, p. 311, et seq., to trace it in its more particular details. 

 II. Meyer (1. c.) agrees with me in most of the essential points, 

 whilst Robin advances many different views, with which I do 

 not accord, and has to some extent entirely misunderstood my 

 statements.] 



§ 101. 



The primary cartilaginous Skeleton of the human body, 

 although less complete than the subsequent osseous framework, 

 is still sufficiently extensive. We find as portions of it : 1. A 

 complete vertebral column, with as many cartilaginous, as there 

 are afterwards osseous vertebra, with cartilaginous processes, 

 and with intervertebral ligaments. 2. Cartilaginous ribs, and 

 a cartilaginous, entire sternum. 3. Wholly cartilaginous ex- 

 tremities, with as many and similarly formed pieces as there are 

 afterwards bones, with the sole exception of the pelvic cartilages, 

 which constitute a single mass. 4. And lastly, an incomplete 

 cartilaginous cranium. This primordial cranium, as it is 

 termed (' Mikrosk. Anat./ tab. iii, figs. 1 — 3), forms originally 

 a continuous cartilaginous substance, which corresponds, for the 

 greater part, with the occipital bone (except the upper half of 

 the expanded portion), the sphenoid (except the lamina externa 

 of the pterygoid process), the mastoid and petrous portions of 

 the temporal bone, the ethmoid, the inferior turbinated bones, 



