Page:Microscopicial researchers - Theodor Schwann - English Translation - 1947.pdf/141

Rh velopment are rendered smooth, become distinctly and individually discernible, and assume their waving course; in short, they acquire the appearance of the ordinary fibres of areolar tissue. (See the figure.) As the process of splitting advances from both sides towards the nucleus, the fibres in its neighbourhood are those which are longest united together, and that part of the cell is the last to undergo division. The nucleus remains for a time lying upon the fasciculus of fibres; and when it is at last absorbed, we have a bundle of fibers in the place of the original cell. The figure represents a nucleated cell, which is elongated at the upper end into the characteristic fibres of areolar tissue, each one being individually perceptible; the upper part of the body of this cell has also begun to split into fibres. With regard to the elongation downwards, it is not possible to distinguish whether there are separate fibres yet formed, and collected into a cord, or whether it is still merely a simple prolongation of the cell.

It now becomes a question how the elongation of the cells into fibres, and their division, and at a later period the splitting of the body of the cell also into more minute fibres, can be conceived to take place. We have already observed a prolongation of the cells into fibres in several instances, and have traced it minutely in the stellated pigment-cells. The only difference between them and the fibre-cells of areolar tissue is, that in the latter, the elongation generally takes place in two opposite directions only, a circumstance which also frequently occurs with pigment-cells; whilst, on the other hand, the cells of areolar tissue also frequently become elongated into fibres on several sides; see, for example, pl. III, fig. 8. There is often a striking resemblance in form between some of the cells of areolar tissue and those of pigment; compare, for instance, pl. III, fig. 6 a, with pl. I, fig. 8 e. Analogy would lead us to regard those fibres as hollow; but since the cell-contents are not so characteristic in them as they are in the pigment-cells, a cavity might really exist, but not fall under observation, in consequence of the minuteness of the fibre; the appearance of the fibres, therefore, proves nothing, either in favour of or against their hollowness. Since, however, we are already acquainted-with many extremely minute hollow