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

  • Mellanby, Edward, Sir, 1884-1955.
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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    degeneration was prevented and curative changes were observed. This part of the problem will be discussed in a later paper. Distribution of nerve degeneration in carotene deficient rabbits.—An account will now be given of the more common positions of the different levels of the brain and cord in which lesions are found in rabbits brought up on diets previously described where vitamin A and carotene are deficient. As it is not easy to take low-power photomicrographs of Marchi preparations which show up the degenerated fibres, it was decided to make drawings showing the position and relative amount of degeneration at representative levels. At first it was thought that this would give as accurate a record as the work justified. On further consideration, since it seemed certain that some at least of the fibres involved in more obvious lesions could be identified, as those of the dorsal columns and of the spino-cerebellar tracts, attempts were made to associate more and more of the degenerated fibres with well recognized tracts. This procedure became more necessary when the medulla, pons and mid-brain were examined, as it was desirable if possible to make some kind of a unified story out of what at first sight seemed a mass of disconnected facts. The distribution of the degenerated fibres in the medulla and pons has helped considerably in the identification of degenerated fibres in the cord, for many tracts which are in close proximity in the latter separate out in the higher regions and therefore can be more readily differentiated. I have therefore attempted to describe the actual degenerative changes in terms of well-recognized tracts, in spite of the fact that in so doing some errors may have been made. Although the brain-stem of the rabbit is built up on the same plan as that of other mammals, variations in the size and position of some of its component parts are apt to lead to difficulty in recognizing certain groups of nerve fibres and nerve cells (nuclei). For instance, the inferior olivary proturbances in the rabbit are small as compared with those of man. Again, in the human brain a large band of transverse pontine fibres are seen superficially, while in the rabbit the pons is a relatively small structure (see fig. 1) so that these fibres form a comparatively narrow band. Before attempting to identify the lesions in the affected animals, it was thought desirable to fix the “ land marks ” of the brain of the rabbit as compared with other mammals and for this purpose serial sections (30/* thick) were made right through the brain of a normal animal. Every tenth section was stained with hsemotoxylin after mordanting, so that a general view of the main anatomical and