THE OSSEOUS SYSTEM. 345 



lopraent with the rest of the skeleton, constituting the perma- 

 nent cartilages of the nose, joints, symphyses, and synchondroses ; 



by any one who will without prejudice examine into the subject, but it seems 

 to result from the observations, even of those who have interpreted the facts 

 otherwise. 



Schwann (' Mikros. Unters.,' pp. 112, 113) describing the development of the 

 cartilage of Pelobates, says : " The new cells arise in the cytoblastema (matrix nobis). 



We see at first mere cell- nuclei (corpuscles nobis), which are somewhat 



smaller than the nuclei of the full-grown cells, a, b ; partly nuclei, which are closely 

 surrounded by a cell, c, c ; in short, all transitional forms, from mere cell-nuclei and 

 nuclei surrounded by small cells, to fully formed cells ; so that here, development 



takes place as in small cells, and the nucleus is their actual cytoblast The 



cell-membrane becomes distinct only in the full-grown state." 



In the next page, Schwann speaks of the free-swimming nucleated corpuscles 

 which he obtained from the ossifying cartilage of a foetal pig, and which he considers 

 to be identical with the bodies already described in Pelobates. In reality, however, 

 these bodies are not cells in the same sense, being merely the nuclei of Schwann and 

 the nucleated form of the corpuscles to which we have referred above. 



Whatever Schwann's words may indicate, then, his observations tend to precisely 

 the same conclusion as our own. 



Henle (' Allg. Anat.,' pp. 803 — 808) follow s Schwann, and equally fails to dis- 

 criminate the cells in Pelobates from the "cells" in the foetal pig. 



Reichert (in his admirable work, ' Ueber das Bindegewebe,' 1845) recognises the 

 fact that the cartilage-corpuscles are "nuclei" in Schwann's sense, and refers the ap- 

 pearance of a distinct wall in the cavities, to an optical delusion. He asserts that 

 young cartilage is composed of distinct cells closely united together, without any 

 measurable intercellular substance; as the cartilage grows, the latter increases, and 

 eventually the cell-walls disappear. The only evidence of the existence of these cells 

 and intercellular substance offered by Reichert, however, is the mode in which the 

 tissue may be broken up ; a kind of evidence whose value the purport of the rest of 

 his book is to reduce (and most successfully) to nothing. 



In effect, therefore, Reichert's observations come to the result already stated, that 

 the fcetal cartilage is composed of a homogeneous matrix, in which the corpuscles 

 are dispersed. 



Robin (' Observations sur l'Osteogenie') takes nearly the same view of the structure 

 of cartilage as that we have indicated. " Cartilage is composed," he says, " of a homo- 

 geneous, amorphous, dense, elastic, hyaline basis (substance fondamentale), in which 

 cavities are hollowed out, — the cartilage-cavities. In each of these cavities we find 

 one or many (sometimes 20 to 30) cells, — cartilage-cells, whose parietes cannot be 

 demonstrated to be distinct from their cavity. These cells are more or less granular, 



and have a nucleolated nucleus In the foetus, up to the age of four or live 



months, more or less, the cartilage cavities do not inclose one or more cells, but one 

 or many masses of yellowish granulations, all of nearly the same size. These masses 

 are more or less distinctly defined at their edges, in general indistinctly, and nearly 

 reproduce the form of the cavity without ever filling it. They maybe called cartilage- 

 corpuscles. Authors have not generally remarked this fact. By degrees the cells 

 which replace these corpuscles are developed. These cells are formed all at once 



