Lesions of the central and peripheral nervous systems produced in young rabbits by vitamin A deficiency and a high cereal intake / by Edward Mellanby.

  • Edward Mellanby
Date:
[1935?]
Catalogue details

Licence: In copyright

Credit: Lesions of the central and peripheral nervous systems produced in young rabbits by vitamin A deficiency and a high cereal intake / by Edward Mellanby. Source: Wellcome Collection.

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    twenty-fifth the animal was very inco-ordinate and had difficulty in regaining its balance when put on one side. It was killed on the twenty- eighth week, sixteen weeks after the first signs of nervous abnormality. The second animal B was on diet only eight weeks when it showed the first signs of abnormality, especially slight stiffness and head movements. These gradually increased although there was slight improvement over one period. After the twenty-first week its head was held permanently to the left and there was definite xerophthalmia. It was killed after twenty-five weeks (seventeen weeks after appearance of the first signs), whjen the inco-ordination was great and the head-jerks such that the animal tended to fall over backwards. An examination of figs. 3 to 19 shows the distribution of degenerated fibres and tracts in the spinal cord and brain-stem. In these drawings, black dots represent degenerating fibres as revealed by Marchi method, circles “o” represent fibres which have completely degenerated, and not annular degeneration (see p. 145). I.—Spinal Cord. Ascending tracts.—In the spinal cord degeneration is found in the following ascending paths :— (1) In both tracts of the dorsal columns. It is more common to find degeneration in the lateral than in the mesial column. (2) In the following tracts of the lateral columns :— (a) dorsal spino-cerebellar ; (b) lateral spino-reticulo-thalamic ; [There is reason to believe that the ventral and lateral spino-thalamic tracts consist in part of fibres with synaptic interruptions, especially in the reticular formation of the brain-stem, and the two tracts are sometimes designated as the spino-reticulo-thalamic paths (Page May [5].] (c) ventral spino-cerebellar; and (d) in the spino-tectal; [The fibres of this tract are in the cord associated with the lateral spino-reticular-thalamic tract, but it forms a separate tract in the mid-brain where degenerated fibres are seen (figs. 12 and 19).] (3) In the ventral columns the most prominent ascending degenerated fibres belong to : (a) ventral spino-reticular thalamic (see note 2b above) ; and (b) possibly spino-olivary tracts. Descending tracts.—There are degenerated fibres in the following descending tracts of the spinal cord : {a) the rubro-spinal ; (5) vestibulo-