A treatise on mental diseases : based upon the lecture course at the Johns Hopkins University, 1899, and designed for the use of practitioners and students of medicine / by Henry J. Berkley.

  • Berkley, Henry J. (Henry Johns), 1860-1940.
Date:
1901
Catalogue details

Licence: In copyright

Credit: A treatise on mental diseases : based upon the lecture course at the Johns Hopkins University, 1899, and designed for the use of practitioners and students of medicine / by Henry J. Berkley. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    axis cylinder, wliicli in one variety extends for a very considerable distance from the cell body, while in the other it breaks up into tine terminations in the immediate neighbourhood of the cell body, or at least in a not distant territory. Of the former type the best example is to he found in the pyramidal cells, which have a nerve extension downward to tlie spinal cord, or to the opposite hemi- sphere through the medium of the corpus callosum. The cells with the long axis cylinder are known as motor cells, or, as Schaefer has termed t\\Qm, 2>'i'ojection cells, the impulse generated in them being carried or projected to other and distant regions. The second variety, those with short axis cyhnders, were first thought to be sensitive cells by their discoverer, Golgi, but this idea lias been abandoned, and they are now supposed to play the part of connecting elements between other cells, hence their name interme- diary cells. They are also known as Grolgi cells of Type II. What- ever may be the form of cells of the cortex, star-shaped, pyramidal, pluripolar, ovoid, or other shape, all belong to one or the other of these two types. When we come to study the fine structure of the cell, we shall see that it is provided with a nucleus and nucleolus, a protoplasmic body or corpus, extensions from this corpus of varying number, the neurodendrites or dendrites, which give off short bulbar exten- fiions from their sides, the gemimdcB, and an axis cylinder, neuT- <ixo7ie or axone, of varying length. ]^o brain cell can be said to have more than one axis cylinder, and although several have been described as belonging to certain cells of the most external por- tions of the rind, recent studies have shown that these observations are probably incorrect. The assemblage of corpus, nucleus, proto- plasmic arms, lateral buds, and axone, with its collaterals, together form a nerve entity for which Waldeyer has suggested the name neurone. Each neurone is separate and distinct from its fellow; it exists as an individual unit, from corpus to ultimate ramification— in other words, it does not unite or anastomose in any way with any other of the vast myriads of neurones in the nervous system.* * The recent work of Apathy, who thought he observed the passage of the fibril- lar of one nerve cell into the protoplasm of other ganglion cells, and the researches of Held, who advocates a subdivision of the ultimate axis fibrils within the body of the nerve cell, have not been confirmed by other observers: while the evidence of the silver method, which is clear and distinct in all details, tends to prove conclu- sively that such views are incorrect, at least for the higher vertebrates, and that the relation of cell to cell is by contiguity, each neurone being separate and distinct. See also the recent articles of Lenhossek in the Neurol. Centralblatt, Nos. 6 and 7,1899.