THE OSSEOUS SYSTEM. 313 



to afford sufficient ground for the establishment of his position; 

 and even should it be established, I cannot agree in the explana- 

 tion offered, not being aware of a single fact in favour of the 

 notion of a coalescence of cartilage cells.] 1 



• [We have deferred to this place the remarks we have to make with regard to the 

 structure of cartilage, and its mode of growth ; as a just conception upon this subject 

 appears to us to be essentially necessary to a comprehension of the mode of develop- 

 ment of Bone, — in fact, we might say, to clear notions upon the structure of the 

 tissues generally ; for as we shall show more at length below (Appendix), it was 

 upon the structure of cartilage, anil what be supposed to be its similarity to that of 

 vegetable tissue, that Schwann based the whole nomenclature of his cell theory. 



Now we may so far anticipate what we shall have to show hereafter, as to premise 

 that Schwann was misled upon two essential points, — the first being the supposition 

 that the histological elements of plants and animals are primarily independent cells ; 

 the second, the notion that the "nucleus" of the animal, is homologous with the 

 nucleus of the vegetable tissue. It is, we believe, from the inextricable confusion 

 produced by these fundamental mistakes, which have been adopted by almost all 

 Schwann's successors, that one half of the controversies with respect to the structure 

 of cartilage and the process of ossification have arisen. And yet to one who is free 

 from them, nothing can be simpler. 



We have already (note p. 30) referred to the structure of fcetal cartilage, but it 

 may here be described more at length. We found the cartilage of the septum nasi of 

 a four-months' human foetus to be composed of a homogeneous, soft matrix, without 

 structure of any kind (fig. 129 A, 1, 2), in which lay imbedded, rounded or irregular 

 vesicular bodies, varying in diameter from ^ — j&jgth of an inch ; the commonest 

 size, however, being ^ — . i: ' on th. These "corpuscles" frequently contained one or 

 more granules, sometimes very small, sometimes larger, and of a distinctly fatty 

 nature ; such fatty granules, also, were sometimes to be found in the matrix around 

 the corpuscles. 



The cavities in which they lay, were, for the most part, just large enough to con- 

 tain them, and presented no walls or sharp line of demarcation of any kind from 

 the surrounding substance. 



When the corpuscles were as large as T a 0D th of an inch, they occasionally contained 

 a round body, of rather less than joggth, as a " nucleus." 



The matrix was in some parts pale and indifferent ; but where the tissue had taken 

 on its definitely cartilaginous nature, the chondrinous substance into which it was 

 converted refracted the light much more strongly. In this part also, the cavities in 

 which the corpuscles lay, were often of considerably larger dimensions than the 

 latter, and their walls exhibited a sharp, dark line of definition from the surrounding 

 substance, which was often brought out much more strongly by the action of acetic 

 acid. It appeared, in fact, that the conversion into chondrin had not quite reached 

 the inner surface of the cavities, and hence they were chemically and optically dis- 

 tinguished from the surrounding substance. 



Now, of course, it matters very little what names are given to these parts, so long 

 ;:s they are used only in one sense. Schwann considered the corpuscles to represent 

 the "nuclei" of plants, and therefore gave them that name. Henle, Reicherl 



