Remarks on evolution and dissolution of the nervous system. No. 1 / by J. Hughlings Jackson.

  • Jackson, John Hughlings, 1834-1911.
Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: Remarks on evolution and dissolution of the nervous system. No. 1 / by J. Hughlings Jackson. 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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    such that any discharge of energy is necessarily a full and maximal discharge; there is no partial or graduated dis- charge possible at any moment, apart from the influences of nerve control, distension of the cavities, temperature, &c. A discharge of energy induces a period of exhaustion which renders a second discharge impossible until a certain degree of reparation has been attained; in this way the occurrence of a steady and prolonged discharge—like that of a complete tetanus in a skeletal muscle—is prevented ; hence continued stimulation (e.g., with galvanic currents or weak faradic currents) leads to a series of contractions, and not to a steady tetanus.” So much for “ peculiarities ” of the heart. In the next Section I shall speak of some peculiarities, or rather, signifi- cant associations, of its first representation in the central nervous system. Section XIII. Representation; Re-representation and Re-re-representation of the Heart, in Lowest, Middle, and Highest Centres Respectively ; otherwise. First, Second, a?id Third Representation.—That the heart is represented in the Lowest Level of Central Evolution is accepted doctrine. There are a cardio-inhibitory and an accelerating centre in the medulla oblongata. This is Representation (first representation). There are some facts significant to my main topic to be stated here. The vagus is a sensory nerve, obtaining its inhibitory and motor endowment from the bulbar part of the spinal acces- sory ; the vagus, sensorily, is, among other things, afferent to the cardio-inhibitory centre. It is significant that the vagus nucleus has close relations to the nucleus of the sensory nerve, called auditory (inner auditory nucleus). I say ccilled auditory. One division of the nerve is from the cochlea, for reception of aerial vibrations; the other division is from the semicircular canals (for reception of coarse vi- brations during movements of the body) (?) and serves in regulating locomotor movements in relation to one another. It is significant that the nucleus of the vagus (since this nerve, sensory, is, among other things, reflexly, one regulator of the most rhythmical organ, the heart) has close relations to the inner auditory nucleus. The auditory is the sense pre- eminently appreciative of(^) times—intervals between certain (‘) I do not mean by itself any more than I suppose that impressions on the retina by themselves form, or form part of, the physical basis of extension.
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