The diagnosis of diseases of the nervous system : a manual for students and practitioners / by Christian A. Herter.

  • Herter, Christian Archibald, 1865-1910.
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: The diagnosis of diseases of the nervous system : a manual for students and practitioners / by Christian A. Herter. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    For the support and protection of these million of cells and fibres scattered throughout the labyrinth of blood- and lymph-vessels which go to make up the ner- vous system, there exists a tissue known as neuroglia, which is either homogeneous or finely granular in places where the most delicate imbedding material is required, or dense and fibrous where particularly strong support is needed. One particular form of cell, known as the neuroglia cell, is frequently met with in this supporting tissue. (See Fig. i.) The typical ganglion-cell is characterized by the pos- session of an axis-cylinder process, which is in all proba- bility continuous with the axis-cylinder of a nerve-fibre. Other prolongations are possessed by certain cells, and are protoplasmic in natuie. Whether these additional processes merely subserve nutrition, or afford means for direct or indirect communication from cell to cell by the interlacing of their fibrillary branches, is uncertain. Besides originating and receiving nervous impulses, the ganglion-cells exercise an influence over the nutri- tion of the nerve-fibres and other tissues with which these are in connection. Secondary degeneration of the distal portion of a nerve-fibre, on separation from the cell with which it is united, has already been mentioned. There is also in the course of time some trophic dis- turbance in the cell itself, and the portion of the fibre still connected with it, especially in very young animals. This trophic change is allied histologically to secondary degeneration, but is not precisely the same process. It is a species of dystrophy from non-use, and partakes also of the nature of arrest of development when it occurs in young animals. Nerve-fibres degenerate, as a rule, in the direction in which their nervous impulses travel. Thus, when a