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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    first beginning round the nucleus, a swelling of the whole cell and a movement of the nucleus towards the periphery. All nerve-cells whose conducting fibres are cut do not react in this way. The best reactions are seen in motor cells, as those of the ventral horns or in the cortical motor cells, when their respective conducting fibres suffer transection. Peripheral afferent nerve-cells, as those of the dorsal root ganglion, undergo secondary degeneration when the peripheral portions of the fibres are divided, but not when their central processes, i.e. the dorsal roots, are injured. In the central nervous system itself, apart from the chromolysis and other changes seen in the cells of Clarke’s column when the dorsal spino-cerebellar tract is destroyed, but little is known of secondary cell changes in ascending systems. It is certain, however, that afferent cells in the central nervous system are by no means as susceptible to this type of change as the motor cells. The question of primary or toxic reactions of nerve-cells, the so-called primary degenerations, is even more complex. Since the introduction of the Nissl technique, many investigations have been made to determine the changes produced in nerve-cells by known toxic substances. Nissl [11] himself investigated the action of many such substances including lead, arsenic, phosphorus, mercury, silver, alcohol, morphine, bromide, cocaine, trional, veratrine, strychnine, carbon disulphide, and tetanus toxin. Goldscheider and Flatau [12] also made many investi¬ gations into the effect of pathological conditions produced experimentally on nerve-cells. Kussell [13] has studied the effect of parathyroidectomy on cells of the nervous system, and in more recent times Dye [14] has compared the effect of parathyroidectomy and cretinism on the nerve- cells of dogs. Other harmful procedures whose effects on nerve-cells have been studied include ischaemia, inanition, hyperpyrexia, uraemia, extirpation of the suprarenal bodies, and experimental and natural infection. Although it is undoubted that nerve-cells undergo changes under many of the above conditions, the subject of primary degeneration has remained generally unsatisfactory aud undeveloped. One of the diffi¬ culties in work of this nature is, as Nissl himself recognised, that under conditions which produce primary degeneration of the nerve-cells even one group may show the widest variations, some appearing nearly normal and others having great degenerative changes. Even in normal animals the cells in one group may vary in their appearance. In his studies of the effect of parathyroidectomy and cretinism on the nerve-cells of dogs,