( 226 ) 



probably because the tentorium, ossified in these animals, had been 

 drawn through the occipital pole of the hemispheres. 



With the exception of this damaged portion it was possible to 

 make a continuate series of frontal sections, partly after the Weigert- 

 Pal method, partly coloured by means of carmine, which could be 

 compared with the existing series of frontal sections from brains of 

 normal cats. 



The first thing noticed was that the peripherical octavus-roots 

 which were attached to the oblongata, although smaller than in the 

 compared preparations, had not suffered any change. In accord with 

 this fact no degenerations were found either in the lateral rootfibres 

 upon the corpus restiforme, or in the rootfibres in the ventral nucleus 

 of the VIII th nerve, or in the deep medullated layers of the tuberculum 

 acusticum (speaker exhibits the microphotograms demonstrating those 

 rootfibres.) 



Although these nuclei too are somewhat smaller than in the com- 

 pared series, yet it is impossible that the deafness of this cat should 

 have been occasioned by a prima)-)/ affection of the labyrinth. For 

 in that ease the well-determined and distinctly confined atrophies 

 would have been found in the systems of primary rootfibres, which 

 are in all cases consequent to the removal of the labyrinth in new- 

 born animals. (These atrophies are demonstrated by the speaker on 

 preparations and microphotograms of brainsections taken from rabbits 

 where the labyrinth had been removed shortly after birth). 



Those atrophies however were not found in the brain of this cat. 

 The more striking is the fact that a secondary system of fibres, 

 the dorsal octavus-tract, the so-called stria acustica (v. Monakow) 



"an express investigation with the continuate note-series and with strong sound- 

 stimuli gave only negative results. 



"The statical organ on the contrary was proved to be perfectly normal. On 

 "the 7th of June 1908, shortly before death, this was carefully studied in my 

 "Laboratory. 



"Climbing along the frame of a rotation apparatus was done in the normal 

 "manner, likewise leaping from a chair. During rotation, when shut up in a 

 "blackened chest, with an aperture on the upperside in order to facilitate the 

 "observing of what is going on within, nystagmus of the head and of the eyes 

 "was shown in the usual way. 



"On stopping the apparatus, a typical instance was observed of the well-known 

 "after-rotation, described once again by Mr. van Rossem (Sensations and reflexes, 

 "having their origin in the semi-circular canals Diss. 1907, Utrecht). 



"Upon the small experimentation-lift of W. Mulder, whilst seeing is excluded, 

 "all otolittic reflexes are recognized, and nowise impaired. 



"During life the animal mewed." 



