OF THE NERVUS OCTAYUS. 33 



Of course it would be very important if the deviation of the 

 eye could be counterfeited experimentally. 



The analysis of the opposite eye shows the following phenomena: 



a. small orbital fissure. 



b. protrusio bulbi. 



c. maximal deviation in a direction downward (ventral) and in 

 the nasal canthus (lateral) with a slight rolling of the eye. 



All these phenomena may be the result of phenomena of paralysis, 

 whereas the antagonistic in nervation has been preserved or is even 

 increased. In that case the paralytic phenomena must be: 



a. paralysis of the m. levator palpebrae superioris. 



b. paresis of several muscles of the eye with secundary exoph- 

 thalmus paralyticus. 



c. paralysis of the m. rectus superior-drawing the eye frontalward- , 

 paresis of the m. rectus externus-drawing the eye lateralward- , 

 paresis of the m. obliquus superior-drawing the eye downward 



and rolling it. 



In connection with these paralytic phenomena we must admit 

 a strong antagonistic action , exerted by the m. rectus internus and 

 the m. obliquus inferior to develop the deviation of the eye. 



Basing on this analysis , I now sectioned in rabbits isolated or 

 in combination the m. rectus superior, the m. rectus externus and 

 the m. trochlearis -- all this being done easily by one single con- 

 junctival lesion - - and extirpated pieces from these three muscles, 

 each piece being long at least 1 c.M. 



After this operation however there is never observed any trace 

 of a deviation of the operated eye. Perhaps the muscles are not 

 rendered completely inactive , perhaps the antagonistic hyper-hmer- 

 vation is not excited, probable because under these conditions such 

 an innervation would not serve to any purpose. 



To conclude, I never did succeed in provoking any evident 

 deviation of the bulbus by means of sectioning the bulbus-muscles, 

 far less a position that might in any degree be compared to that, 

 observed after destruction of the labyiinth. 



It remained therefore impossible to decide whether an experi- 

 mental deviation of the eyes was followed by a similar position of 

 head and neck in the same direction, because such a position of 

 the eyes could not be provoked experimentally. 



Still the argument remains valid, that head arid eyes compen- 

 sate one another mutually by the deviations they assume, and this 

 supports the opinion that the turning of head and neck may be a 

 corrective for the position of the eyes. 



Verhand. Ron. Akad. v. Wetensch. (Tweede Sectie Dl. XIV). 



