New observations upon the structure and formation of certain nervous centres : tending to prove that the cells and fibres of every nervous apparatus form an uninterrupted circuit / by Lionel S. Beale.

  • Beale, Lionel S. (Lionel Smith), 1828-1906.
Date:
1864
Catalogue details

Licence: Public Domain Mark

Credit: New observations upon the structure and formation of certain nervous centres : tending to prove that the cells and fibres of every nervous apparatus form an uninterrupted circuit / by Lionel S. Beale. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    that there are nuclei connected with the dark-bordered fibres, near their origin in some instances, and near their distribution in all tissues, as well as in connexion with the pale fibres distributed with them. And there is also the very large nucleus with nucleoli at the fundus of the cell. 5. Of the essential nature of the changes occurring during the formation of all nerve- cells, and of the formation of the spiral fibres. Although ganglion-cells are formed according to the three different processes just described, it will be found, upon careful consideration, that the changes which occur are, in their essential nature, the same in all. In every case it has been shown that what is commonly called the “nucleus” takes an important part in the process; and in the drawings (figs. 5, 9, 15, & 38) the large size of the “nucleus” in the young cells cannot fail to be noticed. In considering the actual changes which occur, it will be better to call the matter which is coloured red by an ammoniacal solution of carmine “ germinal matter,” and the colourless matter around it and continuous with it “formed material.” In young specimens the germinal matter is sometimes seen to gradually pass into the formed material; but in fully formed cells of all kinds there appears a line of demarcation. Neither ganglion-cell, nor nerve-fibre, nor indeed any living tissue exists without there being living germinal matter in connexion with it. On the other hand, masses of ger- minal matter exist before either ganglion-ce//s or distinct fibres are formed. If figs. 5, 9, 14, 15, 16, & 38, which represent young ganglion-cells, be contrasted with figs. 1, 3, 4, 20, & 27, which are taken from fully formed or old cells, the different proportion of “ germinal matter ” to the “ formed material” at different ages will be observed; and it is to be noticed that the youngest cells (fig. 9) consist almost entirely of germinal matter, while in the fully formed cell there is at least from ten to twenty times as much “formed material as there is of “germinal matter' (fig. 1). In the fully formed cell the germinal matter (nucleus) exhibits a line around it, but there is no cell-wall or other structure between it and the granular material which surrounds it. In fact, by the use of high powers, an actual continuity of structure may usually be demonstrated. The smaller centres (nucleoli) also seem to be distinct from the germinal matter in which they lie. Even in these so-called “ nucleoli ” still smaller spherical bodies, to the number of three or four (nucleoluli), are sometimes to be seen distinctly (figs. 26 & 27). These centres are evidently formed one within the other. The last or smallest centres are most darkly coloured. In the “nucleoli” the colour is not so intense. The “nuclei” again are still paler, but nevertheless the colour is very decided indeed. The matter more external is very faintly coloured, or it remains per- fectly colourless. So that in this, as in many other instances elsewhere, it is to be noticed that the outer part of each cell, or that in actual contact with the colouring solution, is not coloured, while the intensity of the colour gradually increases as we