692 NATURE OF FIBROUS TISSUES. 



stance ' which usually constitutes the principal portion of this tissue 

 in its mature condition. And it would appear from the history of its 

 development (which has been carefully studied by Dr. Beale), that 

 the 'intercellular substance,' 'cell-wall,' and 'cell-contents,' are all 

 to be regarded in the light of layers of 'formed material,' successively 

 exuded from the corpuscle of ' germinal matter ' wherein the cell 

 originated, a portion of which remains as the ' nucleus.' 



540. A large part of the fabric of the higher Animals, however, 

 is made up of Fibrous Tissues, which serve to bind together the 

 other components, and which, when consolidated by Calcareous 

 deposit, constitute the substance of the Skeleton. In these, the 

 relation of the ' germinal matter ' and the ' formed material ' pre- 

 sents itself under an aspect which seems at first sight very different 

 from that just described. A careful examination, however, of 

 those ' Connective-tissue-corpuscles' (Fig. 377) that have long been 

 distinguished in the midst of the Fibres of which these tissues are 

 made up, shows that they are the equivalents of the corpuscles of 

 ' germinal matter' which in the previous instance came to constitute 

 cell-nuclei ; and that the fibres hold the same relation to them, 

 that the ' walls ' and ' contents ' of Cells do to their germinal cor- 

 puscles. The transition from the one type to the other is well seen 

 in Fibro- Cartilage, in which the so-called ' intercellular substance ' 

 is often as fibrous as a Tendon. The difference between the two 

 types, in fact, seems essentially to consist in this, — that, whilst the 

 segments of ' germinal matter ' which form the cell-nuclei in Car- 

 tilage (Fig. 385) and in other Cellular Tissues, are completely isolated 

 from each other, each being completely surrounded by the product 

 of its own elaborating action, those which form the ' Connective- 

 tissue-corpuscles ' are connected together by radiating prolongations 

 (Fig. 377) that pass between the fibres, so as to form a continuous 

 network, closely resembling that formed by the pseudopodia of the 

 Rhizopod (§ 326). Of this we have a most beautiful example in 

 Bone; for whilst its solid substance may be considered as Connec- 

 tive Tissue solidified by Calcareous deposit, the ' lacunae ' and 

 ' canaliculi ' which are excavated in this (Fig. 356) give lodgment 

 to a set of radiating corpuscles closely resembling those just de- 

 scribed ; and these are centres of ' germinal matter, ' which appear 

 to have an active share in the formation and subsequent nutrition 

 of the Osseous texture. In Dentine (or Tooth-substance) we seem 

 to have another form of the same thing ; the walls of its ' tubuli ' 

 and the ' intertubular substance ' (§ 545) being the 'formed mate- 

 rial' that is produced from thread-like prolongations of 'germinal 

 matters ' issuing from its pulp, and continuing during the life of 

 the Tooth to occupy its tubes ; just as in the Foraminifera we 

 have seen a minutely-tubular structure to be formed by a process 

 of exudation around the individual threads of sarcode which pro- 

 ceeded from the body of the contained Animal (Figs. 248, 258). — 

 Although there still remains much to be made out, in order to give 



