Nerve-suturing (neurorrhaphy) : degeneration and regeneration following section : microscopical appearances : one of the Mütter course of lectures delivered before the Philadelphia College of Physicians / by De Forest Willard.

  • Willard, De Forest, 1846-1910.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: Nerve-suturing (neurorrhaphy) : degeneration and regeneration following section : microscopical appearances : one of the Mütter course of lectures delivered before the Philadelphia College of Physicians / by De Forest Willard. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    distal portion of another of opposite function. They have traced the various experiments from Cruikshank in 1795 to the present time, and point out the errors of interpretation in various experiments. In regard to pseudo-motor activity of sensory nerves they offer only the explanation of Heidenhain, that it is caused by an increased secretion of lymph, which acts as a stimulus to the partially-destroyed plates of the muscle-fibres, as, for instance, through the chorda tympani fibres of the lin- gual. They believe also that the experiments of Reichert and Schiflf need further confirmation, as sources of error in interpretation are quite possible. They conclude that although the peripheral end of one spinal nerve can unite with the central end of another with return of function, yet that there are no completely satisfactory experiments showing that a pure motor trunk can unite with a pure sensory trunk with return of function to the peripheral portion. They agree with many observers that the myeline disappears after section, and that segmentation begins simultaneously throughout the periph- eral end, in accordance with the testimony of the majority of investigators. The preponderance of evidence seems to be on the side of those who hold that the axis-cylinder degenerates along with the myeline. If we accept the modern view that the axis-cylinder is an enormously elongated process of a nerve-cell, it would follow as a matter of course that this process when severed from its parent cell must degenerate. As to the process of degeneration of the primitive sheath, they are not able to state accurately. Union by first intention, simple and absolute, end to end, without de- generation, cannot be proved; but immediate and rapid return of function has certainly been demonstrated too often for its possibility to be denied. Whether this immediate return is through direct transmission across the minimum amount of space, or whether the restoration of the parts to their normal positions in some way assists other trunks in taking up the function of the injured nerve, is .still uncertain. Those who maintain that new axis-cylinders arise directly from the old ones of the central end have never been able positively to demonstrate their belief. Their conclusions are: 1. That primary union of a nerve without degeneration of the periph- eral end does not / cur. 2. The time of degeneration varies, complete loss of irritability being usually present in from two to four days in dogs, showing that the degener- ative process commences early. 3. The return of irritability and conductivity in a peripheral end after union was noticed at the end of twenty-one days, and it varies at later periods of time, being nearly complete in the majority of cases at the end of eleven weeks. This return of function begins first in the neighborhood of the wound and extends slowly centrifugally, although the branches do not improve in regular anatomical order.