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.

    57/716 page 25
    Changes of form in the Dendrites.—Demoor, Stefanou'ska and Manouelian claim to have demonstrated that, independently of the slow movements of growth of the prolongations during their development, there are other extem- poraneous movements, which give to these prolongations variable appearances and dimensions, following two conditions, the one of activity, and the other of repose. In examining the dendrites of the cells in the braiUs of animals killed in these two conditions, these authors have found that they differ in the following points. In the one case these dendrites bear at their extremities and laterally pyriform prolongations ; these are met with in brains investigated in their noi’mally active condition ; in the other case these prolongations have disappeared into the trunk vdiich supports them, which has assmned a varicose aspect in conse- Fig. 13.—Pyramidal cells of the marmot in two different conditions (after Querton). On the left, pyramidal cell of the marmot awake ; on the right, that of the marmot asleep. quence of their absorption : this condition is met with in morphia poisoning, anaesthetic sleep, and sleep succeeding prolonged fatigue, itself the result of violent stimulation. The preceding authors are unanimous in regarding these changes of form as explaining the two conditions, the one of functional activity, the other of abeyance ^of function, of nervous groups : the first of these two conditions being rendered possible by the establishment of connexions between the elements 'which help to make up a system, the second resulting from a temporary rupture of these connexions.—Whether these changes are definitely connected with special states of the nervous system, may be decided by experiment ; but that they explain these conditions, is more difficult to admit. Kolliker has brought forward the following arguments against nervous amoeboism : the axis cylinder- on which we are able to experiment is not contractile ; the nervous prolongations
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