TISSUES OF THE BODY. 



237 



so that we may only meet with fasciculi intermixed with elastic elements, 

 but without a trace of the original formative cell (comp. fig. 201-203). 



We must still leave it an open question, whether lymphoid cells which 

 have wandered out of the foetal blood-vessels may not be transformed 

 into formative cells of connective-tissue. It seems, however, probable. 



The mode in which elastic fibres have their origin, though compara- 

 tively easy to observe, has been long a subject of controversy. And 

 although the manner of their separation from the interstitial substance 

 remains up to the present completely unexplained, still there can be no 

 doubt that they originate independently of the connective-tissue cells. 



In 136 we spoke of the ligainentum nuchse of the adult mammal as a 

 mass abounding in elastic fibrous networks, and in which no corpuscles 

 are to be found. Now, it was from this tissue in question that Muller, 

 and subsequently Henle and Reichert, obtained proof of this. 



If we examine the ligamentum nuchae of very small foetuses, we observe 

 the same to consist of numerous spindle-shaped cells arranged longi- 

 tudinally, and of an intermediate substance with- 

 out any elastic elements. Later on (fig. 231, A), 

 we recognise exactly similar fusiform cells, with 

 considerable sized nuclei and short pointed ex- 

 tremities (a). Between these there appears an 

 indistinctly fibrous matter (ft). Even here 

 nothing is seen of the elastic elements until 

 the whole has been treated with boiling potash 

 (B), when the cells are destroyed, and a net- 

 work of extremely fine elastic fibres becomes 

 visible. 



If we continue our research on older embryos, 

 we find these fusiform cells becoming thinner and 

 longer until they gradually disappear. In the 

 new-born animal only traces of the latter are to 

 be seen. The elastic networks increase in density 

 in the same proportion, and their fibres in 

 strength. The bundles of connective-tissue also 

 become more apparent in the ligamentum nuchae 

 (Koelliker). 



The above sketch of the development of con- 

 nective-tissue will, no doubt, receive, through 

 continued research, many additions, the more so 

 as our acquaintance with the subject must be 

 looked upon as being merely in its commencement. 

 If we inquire into the mode of appearance of 

 connective-tissue in the body, we find that it 

 may be classed into a primary and secondary. 

 The primary is from a metamorphosis of the cells 

 of the middle germinal layer. The secondary, 



also from the same embryonic layer (never from the corneous and' 

 intestinal glandular leaf), takes place usually from other members of 

 the connective-tissue group, most probably from lymphoid corpuscles. 

 As an instance of secondary formation of connective-tissue, we may 

 cite the process of the production of bone to be described in the 

 following section. 



In pathological novogenesis, also, the formation of the tissue takes 



B 



Fig. 231. From the ligamec- 

 tum nuehse of an embryonic 

 pig 8 inches long. A,- la- 

 teral aspect; a, fusiform 

 cells in fibrillated ground 

 substance, 6; 5, elastic 

 fibres, c, rendered visible by 

 boiling in potash. (Spirit of 

 wine preparation.) 



