Physiology of the nervous system / J.P. Morat.

  • Jean-Pierre Morat
Date:
1914
Catalogue details

Licence: In copyright

Credit: Physiology of the nervous system / J.P. Morat. Source: Wellcome Collection.

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    Trophic and functional Protoplasm.—In taking into consideration all the data of observation and of experiment which are available concerning the nerve element, I arrived at this conclusion ; viz., that two portions, two different protoplasms, must be distinguished ; the one, primitive or organotrophic, is that which is visible in the nerve cell, in which the nucleus of the latter is immersed ; the other, junctional or nervous strictly so called, is that whose properties we are able to observe in the axis cylinder, when we have separated this latter from its cell of origin.^ AVithout any doubt- the plane of separation between the two is not marked out by the cut of the scalpel, executed by the experimenter in order to render apparent either the trophic role of the one or the functional role of the other. This surface of separation seems to be accurately defined in the preparations of Apathy and Bethe. Having thus localized (in the interior of the neuron) nutrition on the one hand and function on the other, it is necessary to understand that these pheno- mena are mutually interdependent, and that the structures which represent them are, hence, in a constant condition of exchange and of mutual dependence. In the neuron, in every cell, as in the entire organism, nutrition and function are but very distinct points of view of an assemblage of functions, ail of which tend to the same end : the conservation of life. 4. Physiological data.—Before the doctrine of neurons had been suggested, physiology had already furnished proofs that certain nervous elements terminate in a definite manner in certain localities which experiment pointed out. These localities correspond exactly to certain of those in which anatomy really establishes the points of contact between the neurons, namely, the ganglia of the great sympathetic. In order of precedence, these are the facts on which this opinion was founded. (1) If the chain of the great sympathetic be stimulated below the first thoracic ganglion (with reference to the vaso-motor nerves pro- ceeding to the ear), the auricular vessels contract. If this chain be stimulated above this ganglion, these vessels dilate. The dilators of - the auricular vessels end in these ganglia (Dastre and Morat). (2) If the sympathetic chain be stimulated either above or below the lumbar ganglia (with reference to the inferior extremity), the hair stands on end in certain areas of the latter. But if these ganglia be impregnated with a solution of nicotine, stimulation applied below continues to cause erection of the hair, but when applied above has no effect. There is a spino-ganglionic element ivhich possesses the function of erecting the hair and which teryninates in the ganglion (Langley and Anderson). ‘ The specific nature of the Neurons.—In accordance with the law of division of labour, which we find is applicable to the nervous system, as to the whole organism, the neurons should possess specific functions. ^ This is clearly the idea which has been reproduced under slightly different names, of distinguishing in the neuron a, tropho-plasma (tropho-protoplasm) and a kineto-plasma (functional or nervous protoplasm strictly so-called).
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