On the mammalian nervous system : its functions, and their localisation determined by an electrical method / by Francis Gotch and Victor Horsley.

  • Gotch, Francis, 1853-1913.
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: On the mammalian nervous system : its functions, and their localisation determined by an electrical method / by Francis Gotch and Victor Horsley. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    iirouiid llio seat of lesion, .siniilar inoveineiits of tlio upper limbs. That .such rellcx movements were present in the case of Worosohiloff's own experiments, is evident from tiie studv of the account of tho.se evoked in the ;iiilinal after the operation iiad heen made upon tho coi-d. Thus, in one (if his experiments (VI.), the animal (Kalihit), was subjected to an operation involving the division of the spinal cord in the dorsal I'egion, the whole cord being cut through with the exception of the lateral tract of the left side. On examining the animal an hour or two afterwards, the right hind limb was found to be paralyzed, due to section of its efferent spinal tract, this efferent paralysis being confirmed subsequently by dividing the cord below the medulla and stimulating its distal cut section wlicn only tlie left hind limb responded ; notwithstanding this, pressure on either foot caused movements in l)oth liiiid legs. Now in this case the movement of the right leg must obviously be a reflex eflect, having its central physiological seat in the lower fragment of the cord, and any arguments based upon the amount of movement of the respective limbs, must deal with the question as to the extent to which the section has heightened or depressed the normal excitability of the reflex centres in this lower fragment. But it is precisely this question which it seems to us has not been sufficiently dealt with in the text, there being a tendency to treat the cord in an unantesthetised animal as if one of its main jjhysiological characteristics, reflex excitability, were in abeyance in the distal, though not in the proximal and central portions. The evidence cannot, therefore, be considered as adequate to warrant his statement : Meine bis dahin vorgelegten Beobachtungen bestlltigen und erweitern die Angaben von Miescher, Nawrocki und DiTTMAR, denn von mm an siud wir darauf liingewiesen, die Bahn, welche das Gehirn mit alien Nervenwurzeln verbindet, in dem Seitenstrange zu suchen. . The criticism just advanced is not a new one since it forms the basis of the objections of Chauveau, Schiff, and others. Its cogency is increased by the discovery made l)y Fodera of hyperfesthesia after section. The most important points in connection with this fur our present purpose are those brought out by experiments made by Schiff* before the observations just referred to. These were, that in many cases of hemisection of the cord there is not merely hyperfesthesia below the lesion t)n the side of the section, but heightened reflex excitability of the cord in the neighbour- hood of the lesion both above and below. This hyperexcitability is less marked when the whole cord is divided, than when a bridge joins the parts above and below the lesion. It has been found by MARTiNOTTit that tlie hyperfesthesia is particularly bound up with injury of a particular region in the lateral column, and It is atti'ibuted by him not to a dii-ect increase in excitability, but to the removal of inhibitory, i.e., depressant, influences by the section. It may be pointed out that, as regards the nerve trunk, the experiments of Hering show conclusively that the hicrease of * Schiff, ' Leln-bucli d. Physiol.,' 1859. t Maetikotti, Hj-peraestliesie nach Verletzung des Hiilsniarkes,'' ■ Arcliiv f. Auat. mid Pliysiol.' (Fhysiol. Abth.), 1890.