170 C. WINKLEE. THE CENTRAL COURSE ETC. 



not roll like rabbits, but prefer, turning the head voluntary until 

 360 has been demonstrated long ago by EWALD. 



As soon as both labyrinths are lost, the similarity of the motor 

 disorders in the two species of animals is striking again. All muscles 

 are atonic. To this in rabbits there is perhaps one exception difficult 

 to explain, as the motor V th nucleus stands unaltered among the 

 degenerate fibres of the octavus-system. 



In fact however, the difference of the motor disorders following 

 the loss of one labyrinth, apparently so great between rabbits and 

 pigeons, is in accordance with the different anatomical distribution 

 of their nervi octavi. 



There may arise many controversions upon the subject to what 

 extent in different animals primary rootfibres are found in the 

 secundary systems. I do not believe these controversions to have 

 a fundamental value. The preponderance of the secundary systems 

 augments with the relative high development of the whole octavus- 

 system. They subentrate for the primary fibres. 



For instance in dogs, there are found less numerous primary 

 fibres between the secundary of the corpus trapezoides than in rab- 

 bits and if VAN GEHUCHTEN be right, in guinea-pigs they should 

 be missed totally there. 



I for myself believe, that even among animals of the same 

 species the relation between rootfibres and secundary is different 

 too. In rabbits for instance, in the corpus trapezoides, it may vary 

 from a few only to very many, but I never missed them there. 



Of more value and still more determining the physiological be- 

 haviour of one-sided operated animals, the correction of the motor 

 disturbances seem to me. There may be a correction by means of 

 the ameliorated function of the remainings of the damaged system, 

 and there may be one , by means of substitution of quite other systems. 



I do not believe that in rabbits the lost function is much restored 

 neither by the same-sided cerebellum , nor by the motor area of 

 the cortex cerebri , at least substitution of all lost function is 

 impossible there. Yet I found though not constant - - atrophy 

 of the same side of the cerebellum and of the motor area in the 

 cortex , if new-born animals were operated long ago. 



Such atrophies necessarily are tertiary atrophies and therefore 

 they are inconstant. They may perhaps throw new light upon the 

 different manners in which substitution of the motor disorders may 

 occur after the loss of the labyrinth. 



