SECT. 91 •] OSSEOUS SYSTEM. iyf 



arranged with their surfaces parallel to the lamellae, and, accord- 

 ingly, directed, for the most part, inwards and outwards. In 

 transverse sections, they present the same characters as those of 

 the Haversian systems, but, except in the smallest cylindrical bones, 

 are little or scarcely at all curved. In sections, whether perpen- 

 dicular or parallel to the surface, they exhibit the same relations as 

 those above described, but with this qualification, that, as might 

 have been expected, a larger number of lacunas are seen flatways 

 in the same section, and that the above-mentioned cribriform 

 appearance, which gives the bones a great resemblance to certain 

 Bections of the teeth, is more frequently observed. The canaliculi 

 of these lamellae partly anastomose as usual with each other, partly 

 terminate upon the outer and inner surfaces of the bones. Where 

 tendons and ligaments are inserted iuto bones, the canaliculi of 

 the outermost lacunae are, perhaps, connected with the adjoining 

 plasm-cells of the fibrous tissue, or end in blind extremities, which 

 last condition is always found in the parts covered with cartilage 

 (articular extremities, ribs, surfaces of the bodies of the vertebrae, 

 etc.). In the trabeculae, fibres, and laminae of the spongy sub- 

 stance, the lacunae have all possible directions ; but are, for the 

 most part, arranged with their long axes parallel to those of the 

 fibres, trabeculae, etc., and with their surfaces directed towards the 

 medullary spaces. They also here intercommunicate by means of 

 their canaliculi, which, where they proceed from the outermost 

 lacunae, open into the medullary spaces. 



Within the lacuna, Bonders and I found a clear, probably 

 viscid fluid, with a cell-nucleus. If bone-cartilage be boiled in 

 water, or in caustic soda, from one to three minutes, these nuclei 

 come into view very distinctly, or dark corpuscles appear, which 

 arc to be regarded as the contracted cell contents, together with 

 the nuclei, and thus analogous to the cartilage-corpuscles. Sub- 

 sequently, Virchow (seeWilrzb. Verh., No. 13) discovered that the 

 lacunae and canaliculi can be isolated by macerating bones in hydro- 

 chloric acid as stellate cells; a fact which, although confirmed by 

 me and others, was not fully appreciated until the doctrine of the 

 primordial utricle was applied by Remak and me to animal cells, 

 and Virchow had demonstrated the conversion of plasm-cells into 

 bone-cells. Accordingly, Virchoic's bone-cells are to be ranked 

 witli the primordial utricles of the cells of ossifying cartilage, and 

 the plasm-cells of periosteal deposits ; whilst the lacunae, in the 

 latter case, simply represent gaps in the matrix or basal substance ; 

 but in the former, are cavities within the thickened capsules or 



