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.

    10/278 page 274
    (1.) Latent Period.—The interval of time occupied in the passage of a nerve iiii])ulse from the afferent to the efferent side of a (reflex) bulbo-spinal centre is given on p. 481, to whicli reference is directed. (Wunut, Exner, and others.) (2.) Excitability.—This function of the grey bulbo-spinal matter is modified by the same causes as those which influence the Cortex, see pp. 272 and 483. When the excitability of the cord is raised, e.g., that of the distal segments after section, these latter may discharge in a coordinated fashion, see p. 423, as was first observed by Schiff. (3.) Mode of Discharge.—The bulbo-spinal centres, like tlie cortex, present three modes of discharge, but not in the same degree, e.g., the combined sequence of tonus and clonus though sometimes present, see j^p. 483-499, nevertheless occurs but rarely. Further, as evidenced by muscular responses, the bulbo-spinal centres appear to dis- charge at regular intervals under certain conditions of isolation and excitation, e.g., ankle clonus (V.H.). For further detail see p. 483. (4.) Nature of the Discharge, (a.) As in the case of the cortex cerebri tlie charac- ter of the muscular response to excitation of the cord is different from that seen when the excitation is directly applied to the nerve. (h.) The tonic contraction is usually developed more rapidly than that obtained from the corona radiata. (f.) The rhythm of the intermittent muscular contractions, fused or not, is ft'om 8 to 10 per second or frequently the early multiples of this rate. (5.) Relation of the Discharge to the Parts of the Body. — (a.) Localisation of the representation of the gross divisions of the body to difierent regions of the bulbo- spinal appai'atus is well marked. (All authors.) if.) Localisation of the representation of the segments of the gross divisions and tlie character of their respective movements to different root-origins in the grey matter. (Fereiee and Yeo, Schiff, Forgue, Beevor.) IL Paths. Functional Activity of the Efferent Paths. The graphic method only permits of a limited analysis of paths, i.e., fibres, inasmuch as there is of necessity included the bulbo-spinal system of centres for the purpose of giving the muscuhir contractions used for record. Hence no result bj the graphic method can be regarded as pure; moreover, it only furnishes information upon the functions of efferent paths. In fact, there is no direct evidence forthcoming from any method of observation, except that of the galvanometer, to prove that the paths themselves in the cord are excitable. Indeed, it has long been held by many physiologists that all eti'ects obtained from stimulation of the spinal cord are due to primary and progressive
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