20 C. WINKLEll. THE CENTRAL COURSE 



A glance on the subjoined photo may show better than any 

 description, how the characteristic attitude of the eyes (reaching 

 its acme again when the head is kept straight) presents itself, the 

 head being put in a straight position, three weeks after the operation . 

 (See lig. 6 and fig. 7). 



As it is said already, the attitude of the eyes is slowly amelio- 

 rating, and when it has been somewhat reduced, occasional shocks 

 of nystagmus recur continually, always in this manner that by an 

 active violent jerk the eyes are brought again into their maximal 

 deviation, and return then gradually into a yet evident deviation 

 but of a less intense degree. 



As soon as the animal (that hitherto was bound, and was there- 

 fore constrained to keep its head straight) has been loosened and 

 set on its legs , or laid down on the operated side , a new tempest 

 of involuntary movements does follow. The head is turned with 

 extreme vigour towards the operated side , in such a manner that 

 the cheek on that side is put down to the ground. Sometimes 

 even the turning of the head is so excessive, that the dorsal part 

 of the head - - turning towards the operated side - - touches the 

 ground. Simultaneously with this movement of the head , the upper 

 limb opposite to the operated side is extended and abduced as far as 

 possible from the body. With this limb the animal is scratching 

 the ground, as if trying to support itself by its leg in order to 

 prevent further turning. 



Generally however it does not succeed in this. 



The animal is beating the air desperately with the foreleg 

 opposite to the amoved labyrinth. This foreleg, still abduced 

 and extended as far as possible, rises and rises (fig. 8 A--C), 

 until at last it has got into a vertical stand. The dorsal part of 

 the head touches the ground, at this moment, for the turning 

 upward and the lifting of the opposite shoulder, subsequent to 

 the turning of the head , is the cause of the motion of the foreleg. 

 As soon as the foreleg has crossed the vertical level , another move- 

 ment appears. The animal cannot maintain the hind-part of the 

 body in the habitual attitude , now that the fore-part of the body is 

 so far turned. It has done so, until the fore-leg had reached the 

 vertical level , (or until the dorsal part of the head had touched 

 the ground), but the turning of the head still continues. Now at 

 once the animal subverts the hind-part of the body and also turns 

 it to the operated side. 



Doing so the animal has then rolled round its longitu- 



dinal axis in the direction of the operated side, and it is not 



