152 Miscellaneous. 



neighbouring integuments, the other drawn out into a long pro- 

 cess, which is likewise attached to the inner surface of the respi- 

 ratory tube. The cell and its prolongation are lined with a thick 

 but very elastic membrane. In the centre of the cell-body we 

 observe a very large spherical nucleus ; this is surrounded by an 

 abundant protoplasm which fills the whole cell as well as its process. 

 It must be noted that around the nucleus the protoplasm is opaque 

 and strongly granular, while elsewhere it is transparent. 



In the interior of the element that we have just described there 

 is developed a long elastic fibre, exactly similar in physical pro- 

 perties to the elastic fibres which are observed in the cervical ligament 

 of a mammal for example. It appears, in fact, under the aspect of 

 a perfectly cylindrical refractive thread, rectilinear when stretched, 

 curled and coiled up when left to itself ; further it may be remarked 

 that it is unalterable by acetic acid and by potash. 



In the cell that Ave have described above the elastic fibre is 

 coiled upon itself a great number of times around the nucleus, 

 in the granular part of the protoplasm, and extended in a straight 

 line into the prolongation of the cell, at the extremity of which it 

 terminates. The elastic fibre is attached by one of its ends to the 

 terminal extremity of the prolongation ; by the other it amalga- 

 mates with and attaches itself to the protoplasm of the cell by means 

 of a sort of branched enlargement. 



When traction is applied to the prolongation of the cell the latter 

 stretches out entirely, and at the same time the coiled portion of the 

 fibre is unrolled ; if it be left to itself it shortens, at the same time 

 that the fibre coils up again in the cell-body. 



The facts just described seem to me to be interesting upon various 

 accounts. In the first place they prove once more to what degree 

 of complexity a simple cell may attain ; in the second, they seem to 

 me to throw a new light upon the morphology of the elastic tissue, 

 since they show us that in this tissue the active part, the elastic 

 fibre, may be developed either in the intercellular substance (Verte- 

 brata) or in the protoplasm of the cells themselves, as I have just 

 described in Erisialis. 



I may remark that striated muscular tissue presents analogous 

 variations, since we see its active parts, the fibrillae, sometimes be- 

 longing really to the protoplasm of distinct cells (striped muscular 

 fibres of the heart), sometimes developed at the expense of the 

 fundamental undivided substance which separates the musculo- 

 genous cells (alar muscles of insects). 



Thus it would seem that one and the same tendency presides 

 over the advance of the elastic tissue and that of the muscular 

 tissue, since in both cases, in proportion as the advance is 

 produced, we see the mechanically acting parts (elastic fibres, 

 striped fibrils) quitting the protoplasm of the cells to which they 

 belonged originally, to be developed in the intercellular substance 

 and thus become the undivided properly of neighbouring cellular 

 elements. — Comptes Rendvs, June 2ii, 1884, p. 1552. 



