339 



takes place, to tlie side of the lesion. ^) Usually shortly after the 

 operation r- rotatiori of Ihe eyeballs aroiind their anteroposterior axis 

 in the same direction is present and also «nystagmiform movements 

 of the eyeballs, slow in the sense of the rotations and rapidly back 

 to tlie normal position (loc. cit.)- 



In the latter stages the only sj'mpton I'ecalling- the movements is 

 a tendency to lie down on the operated side, or even a slighter 

 resistance, if one tries to push the animal on that flaidv. 



All this is in accordance with the older experiments of Floukens, 

 ScHiFF and Cyon and the more recent ones of Ewald, Winkler, 

 Bartels etc. abont lesions of the semicircular apparatus and section 

 of the N. acnstico-vestibularis. 



As soon as the rolling movements are completely compensated, 

 it is easy by blindfolding the animal, by causing an emotion or by 

 the dropping experiment of M ; rey (the noi-mal animal lift up by its 

 feet and dropped unvariably comes down on its feet) to bring about 

 again the original rotation . Also in epileptic fits the rotation may 

 reappear. It is peculiar that in ether-narcosis sometimes a rotation 

 in the inverse sense was noted. -) 



All this being the rule for experimental animals, whether it be 

 exclusively the vestibulary root, or also the acoustic nerv^e, the 

 tuberculum acusticum, the corpus restiforme and the crus medium 

 cerebelli, are simultaneously hurt, for the anatomical connections of 

 the N. Vestibularis those individuals especially have value, whereby 

 — more or less by accident — exclusively the vestibulary root was 

 partly or totally degenerated. 



Here I must mention rabbit V, where the pars petrosa cerebelli 

 was extirpated and as an exclusive associated lesion the N. Vesti- 

 bularis happened to be hurt. Here we could follow up the degene- 

 rated nerve-sheaths pre-eminently to three celgroups : to the trian- 

 gular part of the Deiters Nucleus and its descending Ramus, to the 



3) The direction of the locomotion associated with the forced movements, is 

 judged by the original position of the animal itself. As also this does not preclude 

 the mixing up of these conditions (eg. a sick person, lying in bed on the back- 

 side, presents negative geotropy, compared with all other mammals), the primary 

 position of the animal is always reduced to that of the simplest vertebrate with 

 the simplest forced movements, viz. of tishes. This detail will prove of importance 

 as soon as we proceed from the analysis of the forced movements towards 

 that of the various pathological conditions of the ocular movements and towards 

 that of the various pathological conditions of the ocular movements, conjugated 

 deviations and other neurological syndrom.s. 



2) Compare PasiioN Russell, Phil. Transaction CL XXXV, p. 837, 1804 and 

 RoTiiFiLD Pflüger's Arcliiv. Vol. 49, p. 440 li>i2. 



22* 



