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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    along fibres which do not pass out of these columns, and a strict localisation of nerve impulses i.s with this intensity of stimulus possihle. The posterior columns are particularly susceptible to injury, since they are especially exposed to danger of drying, &c., in the pre])aration of the cord. This circumstance must be always kept in view when experiments involving an intervening exposure of the cord are made. We were muth puzzled by the result of two experiments in which, after dividing the cord in tlie dorsal and luinl)ar regions, we had exposed a portion of the experimental tract in the intervening part, about the 12th dorsal, for subsetpient operative lesion. The following results were obtained :— Dorsal cord e.'ccited. Stimulus. Lumbar coi ■d observed. Le ft. Right. Observed cud. Excited end. Cat (.-510) Lat. Post. Lat. Post. 2nd lumbar 8th dorsal min. 90 31 103 28 max. 190 91 130 85 ma.x. 1G5 65 98 115 Cat (371) 1st lumbnr 9 til dorsal min. 145 112 140 124 mm. 132 98 144 104 max. 170 190 240 182 max. 280 145 192 195 max. 142 179 U,-3 205 General mm. average . 62 42 73 30 1.53 106 141 117 In these cases therefore all lateral column efiects averacfe with minimal stimulus 111, with maximal 166; wdiilst all posterior column effects average with minimal stimulus 70, with maximal 145. It Is seen that these results are exceptions to the general rule (see p. 385) of the effect from the posterior being in the Cat larger than that from the lateral. That this was really due to the prolonged exposure at the 12th dorsal injuriously affecting the posterior columns is shown by the fact that such exceptional results were only obtained when an intervening portion had been thus exposed. If prolonged exposure is avoided by performing the necessary operation mmediately before the desired intervening lesions are to be made no such lowering of the amount of the posterior column effect is observed. . In this relation it is possible to explain the comparatively small posterior column effect (see p. 385) of the Monkey as in some measure clue to a lo,ss of excitability in these columns, which seem to be much more susceptible than the laterals (Chauveau). Injluence of Section of one Posterior Column.—It is possible to interrupt one column only, and thus to obtain conclusive evidence of the extent to which the