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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    vertical meridians deviates to the left, the upper portion to the right, a rotation therefore in the same sense as the rolling movements (Fig. 4, A, B). In the rabbit one finds with the same constancy the upper part Fig. 4. of the right pupil rotated backward, the upper part of the left pupil rotated forward. We notice therefore a most striking difference in the behaviour of the eyeballs of the cat on the one hand and the rabbit on the other. In the cat one finds both eyes deviated in the same horizontal direction and also rotated along the visual axis in the same direction; whereas in the rabbit not only the eyeballs deviate, the right one down, the left one up ; but also the deviation in the horizontal plane, in contrast to the rotation around the visual axis, takes place in an opposite direction. It appears that the two entirety separate visual fields of the latter animal do account for a different way of coordination of the motor nerves of the eyeball, (iii) In the cat it is also easy to see that the rotatory nystagmus usually occurring in the earlier days after the operation is synchronous on the two sides, while the direction of the quick jerk of the nystagmus is directed contrariivise to the deviation above described; i.e. the right eye will jerk upward and to the left; the left eye downward and to the right. The rotatory jerk is equally directed contrariwise to the rotatory deviation. This form of nystagmus therefore is nothing else than a rhythmic jerking opposite to the direction of deviation and toward the normal position of the eyeball1. It will cease a few days after the operation and can then be 1 It will be pointed out elsewhere that the nystagmus, elicited by operative lesion of some parts of the cerebral hemisphere, presents different features. The form of nystagmus here alluded to is, as regards direction of quick movement, in striking contrast to that one of Gowers (Transactions Ophthalmol. Society, iv. p. 309), with a small diseased area on the It. side of the pons above the Vlth nucleus, where the nystag- mus was in the same direction as the deviation.