Neurologic progress and prospects : chairman's address, delivered before the Section on Nervous and Mental Diseases of the American Medical Association, at the Fifty-fourth Annual Session, held at New Orleans, May 5-8, 1903 / F.W. Langdon.

  • Langdon, Frank Warren, 1852-1933.
Date:
1903
Catalogue details

Licence: In copyright

Credit: Neurologic progress and prospects : chairman's address, delivered before the Section on Nervous and Mental Diseases of the American Medical Association, at the Fifty-fourth Annual Session, held at New Orleans, May 5-8, 1903 / F.W. Langdon. 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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    No supreme discovery or demonstration approaching in importance that of “the neuron” has been announced. Yet a steady advance has been kept up along the “firing line,” and the skirmishers, represented by the workers in research laboratories, have penetrated farther than ever into the territory of the heretofore unknown with noticeable advantage to the position and strength of the “main army.” While “the neuron” maintains its position as a “star of the first magnitude” in the neurologic firmament, its lustre has been perhaps a trifle dimmed by the observa- tions of Bethe and of Ballance and Stewart on “The Healing of Nerves.”3 Briefly, these appear to affect the neuron doctrine as follows: 1. They indicate that destroyed axis cylinders of per- ipheral nerves are reproduced, not by down growths from the proximal ends of the cut or degenerated axons, but by proliferation of neurilemma cells of the separated portions of the axis cylinder. 2. These observations also indicate that a peripheral axon (axis cylinder) is not originally a mere outgrowth from a single spinal neuron body (nerve cell), but is a result of the fusion of a chain of ceils, the prototypes or equivalents of other chains represented in the neuri- lemma. 3. When the axon is destroyed the remaining neu- rilemma cells take up the task of producing a new one by proliferation and end-to-end fusion of new cells. Two facts stand out prominently in this connection. First, that these observers admit that development is more or less incomplete unless the newly reproduced dis- tal segment is eventually joined to the proximal end; another illustration of the law that structure is de- pendent on function. It will also be noted that these observations apply to peripheral neurons only, and do not in any way affect the status of the central neurons, since their axis cylinders are devoid of neurilemma, and hence must ap- parently depend on their neuron bodies for trophic in- fluence. Moreover, reproduction of these central axons when once destroyed is almost unknown, only a few observations on the subject existing in the literature (Worcester) .4 The painstaking and admirable observations of Apathy,6 extending over a period of fourteen years and