1098 



been possible to quite spare the pyramidal tract, which could be 

 easily observed in the animals. During the first days after the 

 operation the walking took place with great difficulty. The animal 

 not only was ataxic, but more or less paralysed, often falling aside. 

 Within 10 or 14 days however it had recovered in so far, that it 

 could walk in a straight direction. When it had almost totally 

 recovered, then I passed on to the second operation, and through 

 the right bulla ossea, according to the method of de Kleyn'), the 

 labyrinth and the vestibular nerve were destroyed. 



In five cats the operation succeeded as we wished it. The symp- 

 toms they showed were in general the following: 



a. After transsection, on the right as well as on the left of the 

 posterior funicular tracts and of the spino-cerebellar tracts, ataxia 

 and paralysis resulted, as mentioned above. That ataxia occurs after 

 transsection of the tracts of Flkchsig and Gowkr was already known 

 to us from the investigations of Makburg and Bing. ') The palsies 

 were the results of a not wanted lesion of the lateral pyramidal 

 tracts when transsectioning the spino-cerebellar lateral tracts. After 

 a fortnight these symptoms diminished, the animals could walk 

 rather well in a straight direction and then I went on to the second 

 operation, destroying this time the vestibular organ and the fibres 

 originating from it. 



b. After the 7^i(/ht labyrinth was destroyed and when the animals 

 awakened from the narcosis, they showed in most of the cases all 

 the symptoms, known and found as result of the operation. Always 

 to be observed were eye-nystagmus towards the sound side, on the 

 other hand, retraction of the third eye-lid, narrow pupil and narrow 

 eye-slit (trias of sympathetic palsy, de Klein and Socin ') ) on the 

 sick side. Nystagmus of the head I never observed, however I saw 

 turning of the head towards the operated side. In some cases this 

 turning was distinctly, in other cases less distinctly visible. 



c. Soon after the operation the animals exhibited a more or less 

 marked circns gait towards the sound side, i.e. towards the left. 

 Several degrees of this deviation were observed. In the most pro- 

 nounced cases the animal rotated as it were around its tail. When 

 the circus gair was not distinctly pronounced, then the animal walked 



1) A. DE Kleyn, Zur Technik der Labyrinthextirpation und Labyrinthaus- 

 schaltung bei Katzen. Archiv. f. die Ges. Phys. Bd. 145. 



') See Edingek, Zeitschr. f. Nerv. Heilk. Bd. 45. 1912. bl 303. 



') A. DE Kleyn u. Gh. Socin, Zur naheren Kenntnis des Verlaufs der post- 

 ganglionaren Sympalhicus-bahnen fur Pupillenerweiterung, Lidspalt-eröffnung und 

 Nickhautretraktion bei der Katze. Archiv f. d. Ges. Phys. Bd. 160. 1915. 



