1J04 



right. Proximalhj degeneration appears of the posterior funiculai- tracts, the spino- 

 cerebellar lateral funicular tracts and the spino thalamic tract. This afferent dege- 

 neration too is far more visible on the right than on the left side. Of the spino- 

 cerebellar tracts, the dorsal is the most affected, the ventral (Gower) less. At 

 the right the nervus vestibularis degenerated. 



Cat No. 2. Operation done as in N*^. 1. After the animal awakened from the 

 aether narcosis, it did not show signs that the right vestibular organ was destroyed. 

 Next day the operation was repeated, then with satisfactory result. Noted were 1. 

 Eye-nystagmus to the left. 2. Sympathetic palsy trias at the right. 3. No head- 

 nystagmus 4. No, or very little turning of the head. 



The day after the operation the tat walked rather well, it hardly showed circus 

 gait, but only had an inclination to deviate to the left, hence to the sound side. 



Eight days after the operation of the vestibular organ the cat was killed for 

 examination. This investigation too Prof. Winkler had the kindness to make; the 

 following was found by him : Caudally from the Meld of operation lying between 

 Cj and C3 there is found a rather strong degeneration of the pyramidal lateral 

 funiculai- tract, but contrary I o cat N". 1, there were but few black spots in the 

 tecto-spinal region. Capital wards the posterior funiculi are degenerated and of the 

 spinocerebellar lateral funicular tracts principally the Flechsig, i.e. the dorsal, 

 bundles. Moreover one sees an afferent degeneration within a group of fibres, 

 which originate from the dorsal part of the spino-cerebellar lateral funicular tract 

 of Flechsig. They take their course medialwards, break through the zona inter 

 media, cross in the commissura alba ventralis and take a place in the sulcomarginal 

 region. In following this bundle upwards, it is seen capitalwards of the decussalio 

 pyramidalis against the ventral margin, laterally from the pyramidal tracts. Higher 

 still it is found in the lemniscus in the place, where the spino-thalamic tract lies. 

 As the slides do not reach the thalamus, i could not make out where this bundle 

 ended. All the above mentioned symptoms are more distinctly pronounced on the 

 right than on the left, except of course of the crossed part of the last mentioned 

 bundle. The vestibular nerve is degenerated at the right side. 



Cat No. 3. Operation as with N'. 1. 



After awakening from the aether narcosis there existed I. eye nystagmus to the 

 sound side; II. sympathetic palsy trias to the right; ill. turning of the head to 

 the right; IV. no head nystagmus. The day after the operation circus gait to the 

 left appea'cd, i.e. to the sound side, but this was not half so distinctly pronounced 

 as with cat N'. 1. As was the case with cat N*^. 1, here too the circus gait soon 

 diminished, yet for weeks the animal showed still an inclination to deviate to 

 the left. Also the curved line of gait to reach an object (fig. 1) remainel, 

 although this was not so distinctly visible as in the beginning. 



From a film exposition it proved, that the parade step was distinctly present. 



As the cat already previously had been used for another cerebellar operation, 

 the central nervous system was not examined, as the obtained results might have 

 been influenced by it. 



Cat No. 4. Instead of transsectioning on both the sides of the afferent medullary 

 tracts to the cerebellum, in this cat only the right half was transsectioned. After 

 the animal had totally recovered from the operation, the vestibular organ and the 

 vestibular nerve, as in the three previous cats, were destroyed at the right side. 



After awakening from the aether narcosis the same symptoms were observed 

 as with the other cats, thus I. nystagmus to the left, II. sympathetic palsy trias 

 to the right. III. turning of the head to the right, IV. no head-nystagmus. 



