THE OSSEOUS SYSTEM. 315 



lowish lamella of true cartilage, with thickened cells, not 

 unfrequently beset with calcareous particles, which adheres to 

 the bone not unlike an articular cartilage, though less firmly. 

 More externally we find a cartilaginous substance, in the form 

 of isolated minute, discoid, plates or particles, which appear to 

 be in more immediate connection with the fibro-cartilaginous 

 portions, and between these a connective tissue, with scattered 

 cartilage-cells, as in the insertions of the tendons into the 

 bones (vide § 81). The more exterior portions of the surfaces 

 of the bodies of the vertebra?, corresponding to these parts of 

 the discoid-ligaments, are, in contradistinction to the more 

 internal portions, as it were porous, after the removal of the 

 ligamentous layer ; the medullary cavities or cancelli then being 

 exposed. The pores or cancelli are closed only by the carti- 

 laginous substance of the disc, whilst the fibrous tissue, with 

 its vertical fibres, is firmly connected with the interspaces 

 between them. 



Between the sacrum and coccyx, and the individual coccy- 

 geal vertebrae, are interposed the so-called false inter-vertebral 

 ligaments, consisting of a more uniform fibrous substance, 

 without any gelatinous nucleus. The separate bones of the 

 sacrum, at an early period, have true intervertebral ligaments 

 between them, which afterwards become ossified from without 

 to within, but in such a way, nevertheless, that even in the 

 adult, traces of the ligament may still be perceived in the 

 centre. AVith respect to the nature of the fibres of the 

 intervertebral ligaments, Donders is inclined, especially from 

 the consideration of their chemical relations, to regard almost 

 all of them, not as connective tissue, but as analogous to the 

 matrix of true cartilage, as is also H. Meyer (p. 300, et seq., 

 and p. 310). This opinion may be correct, as regards the central, 

 nuclear portion, and the fibro-cartilaginous laminae of the 

 outer portions, but hardly so with respect to the purely fibrous 

 parts of the latter. I believe, moreover, that it is not by 

 chemistry, but by the study of the development of these 

 tissues, that the question will be solved, because, although 

 manifest, visible distinctions exist between the fibrils of con- 

 nective tissue developed from cells, and the fibrous intercellular 

 substance, viewed from a genetic point of view, chemistry 

 probably is not in a condition to distinguish one from the 



