Studies on the maintenance of the equilibrium of motion and its disturbances, so-called 'forced movements' / by L.J.J. Muskens.

  • Muskens, Louis Jacob Josef, 1872-1937.
Date:
1904
Catalogue details

Licence: In copyright

Credit: Studies on the maintenance of the equilibrium of motion and its disturbances, so-called 'forced movements' / by L.J.J. Muskens. 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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    side and circus to the unimpaired side. This combination manifests itself in the leaps these frogs will make after a few days; they will jump to the left and come down on the right Hank. As a rule immediately after the lesion they perform rolling movements to the right with great vigour; this rolling becomes less marked after a while and is replaced by circus movements to the unimpaired left side, first with a smaller, later with a greater radius. Quite in accordance with what I noted above for the sharks, it was with great constancy observed that the more proximally the hemisection was performed (the base of the mesencephalon being the most proximal point), so much the more the circus movements to the unimpaired side prevailed. These frogs, also those which immediately after the lesion of the base of the optic lobe commence their circus movements and keep them up for many weeks, will keep their head bent over the impaired side, showing a tendency to roll to the right impaired side. Fig. 2. In frogs the forced movements are very persistent. In a good many cases the rigor mortis made its appearance in an asymmetrical way1; this phenomenon is however better studied in warm-blooded animals. If we compare the results reached with frogs and sharks, we arrive at the conclusion, to which point also a number of experiments in various other lower vertebrates:— 1°. That rolling after unilateral lesion of the hind-brain, and circus 1 Starting from the idea that simple forced movements and positions are due to a difference in the muscular tone on the two sides, or some other asymmetrical condition of tone in certain muscle groups, I cut in two specimens of Kana catesbeiana on one side all the posterior roots. In both cases very marked curvature was produced in the bodily axis, with the convexity to the side of the lesion, in one case also the head was rotated along the longitudinal axis to the side of the lesion.