TISSUES, ORGANS, AND SYSTEMS. HI 



is scarcely, perhaps not at all, to be distinguished from genuine 

 connective tissue. There also exists, however, a pathological 

 true connective tissue in cicatrices of all kinds, and perhaps else- 

 where, which is developed from cells ; and for my own part, 

 therefore, I am opposed to the classing together of all connec- 

 tive tissues. We must in our classifications not only distinguish 

 similarity or identity in structure and chemical composition, but 

 embrace all the conditions, and especially the genesis; and thence 

 we must distinguishboththe collagenous fibrous cartilage and the 

 collagenous organised fibriue, from true connective tissue, — just 

 as we separate the true elastic fibre, from the chemically and 

 morphologically, very similar fibres of the reticulated cartilages 

 and from certain forms of metamorphosed fibriue. On the other 

 hand, the connective tissue which has not been developed from 

 cells may justly and properly be arranged with cartilage. 1 



1 [The arguments brought forward by Professor Kolliker in support of his views 

 with regard to the nature and mode of development of connective tissue, appear to 

 us not to preponderate against those of Reichert, Virchow, and Remak, and to be 

 opposed to our own observations, which agree in all essential points with those of 

 the last-named authors. 



There are two questions in dispute. The first, the structure of the connective 

 tissue; the second, the homology of its various constituents with those of other 

 tissues, and of cells in general. 



With respect to the first question, it is admitted on all hands that ordinary con- 

 nective tissue (e. g. of the tendons) is composed of two elements : a, a network of 

 elastic tissue, which is not acted upon by cold acetic acid; b, a substance which is 

 swollen up by acetic acid, and has a more or less fibrillated appearance, contained in 

 the meshes of the elastic tissue. Now it has been demonstrated by Virchow, and the 

 fact is admitted by both Kolliker (supra) and Reichert (Zur Streitfrage iiber die 

 Gebilde der Binde-substanz, iiber die Spiralfaser, &c, Miiller's 'Archiv,' 1852), 

 that the elastic fibres are originally cells, and therefore that they are homologous 

 with the cartilage-cell, i. e. the cartilage-cavity with its wall plus the cartilage- 

 corpuscle or nucleus. That this is the case is very evident, upon examining in a 

 young animal (e. g. kitten) the insertion of the tendo-Acbillis into the cartila- 

 ginous extremity of the os calcis. It is here easy enough to see that the oval or 

 rounded cells of the true cartilage pass in the most gradual manner into the elongated 

 elastic fibres of the true tendon. The cells retain their cavities for a considerable 

 time, but eventually the nuclei and the thin layer of substance which immediately 

 forms the wall of the cavity, become fused into one mass and altered in chemical 

 composition. A like alteration affects the matrix in various irregular directions, so 

 that the delicate elastic connecting fibres are formed, and constitute a network 

 through the whole tendon. These connecting fibres are often branched, and even 

 appear fibrillated at the ends, especially if torn out from their connection with one 

 another, and in this condition they exactly resemble the bodies figured by Professor 

 Kolliker as the "fusiform formative cells" (fig. 29). That thev have nothing to do 

 i. 6 



