On the degeneration of the neurone / [Sir F.W. Mott].

  • Frederick Walker Mott
Date:
1900
Catalogue details

Licence: In copyright

Credit: On the degeneration of the neurone / [Sir F.W. Mott]. Source: Wellcome Collection.

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    the existence in the latter of a complex phosphoretted fatty substance lying between the nucleated sheath of Schwann and the axis-cylinder process. The white fibres of the central nervous system differ from the peripheral white fibres by not possessing a nucleated sheath of Schwann. The myelin is probably con- tained in a neuro-keratin reticulum, and this reticulum is much more abundant in the white matter of the central nervous system than in the peripheral, for Kiihne and Chittenden23 have shown that there is about eight times as much neuro-keratin in the white matter of the central nervous system as either in the grey matter of the central nervous system or the white matter of the peripheral nervous system. In 1884 Weigert introduced his hsematoxylon method for staining the myelin sheath, and by means of this Flechsig24 and his pupils were able to show that certain tracts of fibres of the central nervous system were developed earlier than others. This method and its various modi- fications (Pal, Marchi-Pal and Schafer) have yielded the most valuable results. The different tracts of the posterior columns of the spinal cord were found to be myelinated at different periods, and it was owing to Flechsig’s studies that those of endogenous origin (that is, arising from cells within the spinal cord) were differentiated from those which are exogenous (that is, have their trophic and genetic centres in the cells of the posterior spinal ganglia). The practical outcome of this research was the modern idea of the pathology of tabes, for it was shown that the exogen- ous fibres were alone atrophied in tabes, while the endogenous fibres—viz., cornu-commissural zone of WesphaP' and the median oval area of Flechsig—were spared, these tracts having their trophic and genetic centres in cells within the grey matter of the cord. These facts were recognised as being incompatible with the prevalent view that the degeneration was caused by a sclerosis or overgrowth of the glia tissue in the posterior columns, or by vascular changes ; but they pointed especially to a nutri- tive failure in the trophic and genetic centre by which the out- lying projections of the axis-cylinder processes and their myelin 2:1 Ueber clas Neurokeratin, Zeitschrift fur Biologie, 1890, Band viii. 241st die Tabes Dorsalis cine system Erkrankung ? Neurologisches Central- blatt, 1890, vol. iii. _ . m7 23 Goldscheider; Die Bedcutung dcr Reize fur Pathologic und Therapie im Lichte der Neuronlchrc, 1898.
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