80 GENERAL ANATOMY OF THE TISSUES. 



tissue. We have vet to state how the bundles become chemi- 

 cally aud morphologically what they are. In the first place, I 

 may observe that the formative cells of the connective tissue 

 are not originally distinguishable from the other formative cells 

 of the embryo, do not dissolve by boiling in water, and therefore 

 contain no gelatine. Even when the cells have evidently 

 become fusiform, and have already coalesced into bundles and 

 networks, they still, as Schwann has already stated, yield no 

 gelatine. Therefore, in this case, the change of the cells into 

 a collagenous substance, goes on as slowly as in the matrix of 

 the cartilages, which, according to Schwann, also, at first, 

 yields no gelatine, and therefore it is no objection to the above 

 view of the nature of "Wharton's gelatinous tissue, that it yields 

 no gelatine on boiling, as Scherer has fouud. How the colla- 

 genous matter is formed out of cells, whether the contents 

 only, or the membrane also, takes part therein, it is very 

 difficult to say; in any case, from what we know of the con- 

 tents of embryonic cells, it can hardly be any but a protein 

 substance which yields the gelatine, and, from what takes 

 place in the ossification of the cartilage cells, it seems very 

 probable that the cell-membranes and contents together become 

 metamorphosed into a collagenous substance. 



The morphological change, which the formative cells of the 

 connective tissue undergo, in the course of their passage into 

 bundles of fibrils, is very probably this, that after their mem- 

 branes and contents are fused into a homogeneous semi-solid 

 mass, they then secondarily break up into fibrils ; the latter 

 process taking place in the same manner as we see it occur in 

 the contents of the animal muscular fibres. Herewith, as a 

 rule, the nuclei of the cells eventually disappear, or if they re- 

 main, as we see occasionally in connective tissue, still they 

 never become changed into the so-called nucleus fibres. 



Though in physiological connective tissue, development from 

 cells must be most decidedly affirmed, it does not therefore 

 follow that a substance which chemically and morphologically 

 closely resembles connective tissue, may not arise in a different 

 manner. We know, in fact, that the collagenous basis of 

 cartilage, when it breaks up into fibres, becomes deceptively 

 similar to connective tissue, and furthermore, that fibrous 

 exudations may become changed into a fibrous substance which 



