180 On the Reciprocal Inncrvation of Antagonistic Muscles. 



the opening of the palpebral fissure, but of its closure. The obser- 

 vations having been unavoidably interrupted by removal to a new 

 laboratory, it is only recently I have been able to confirm the pre- 

 liminary observations on a sufficiently extended scale. 



The monkey and the cat have been the animals employed. Under 

 deep chloroform narcosis intracranial section of the Vllth cranial nerve 

 was performed at the point where the nerve plunges into the petrosal 

 portion of the temporal bone. In three instances the nervus od<ti-x, 

 and the pars intermedia, were also severed with the fadalis. In every 

 case the side selected for operation was the left. The facial palsy 

 caused was not detectable so long as the narcosis was maintained. As 

 that was gradually recovered from, asymmetry of expression, &c., 

 became marked. In those instances in which both the facialis and 

 octavus had been severed, there appeared among the symDtoms the 

 following : Rotatory nystagmus of the left eyeball, some inecmality 

 of the pupils the left being the smaller, some degree of impotence of 

 the eyeballs to move so far to the right as to the left, or, expressed 

 more objectively, the eyeballs were never observed to move freely to 

 the right of the primary visual position, although they frequently 

 moved well to the left ; they certainly never moved far to the right ; 

 the animals rolled over about the long axis of the body, as mentioned 

 in Magendie's original description of the effect of unilateral section of 

 the pons. The direction of rotation, if traced from the supine position 

 as starting point, was towards the animal's right side, so that that side 

 next after the back lay undermost. The monkey clutched hold of 

 things within reach, with the apparent intention of preventing itself 

 from rolling. If it failed to obtain some support the rolling would 

 continue through a series of complete turns. This was the condition 

 immediately after complete recovery from the narcosis, and at that 

 time the left knee-jerk was less brisk than the right ; on the latter side 

 it appeared to be abnormally brisk, but it is difficult to fix a normal. 

 The actual existence of section, and whether it had included both 

 nerves or only one, was always determined by subsequent post-mortem 

 dissection. 



As to the eye closure, while the animal was exhausted, or sleepy, or 

 only partially recovered from the chloroform narcosis, there was no 

 obvious difference between the appearance of the eyelids on the two 

 sides, as they rested half open over the globes. When the animal 

 blinked, however, under these conditions, the palpebral opening of the 

 right eye closed, but not that of the left at least not to any easily per- 

 ceptible extent. When on the contrary the animal was fully awake and 

 active, with both eyes well opened, it was seen that as the right eye 

 blinked the left eye also did so. By blinking I understand the rapidly 

 executed movement of closure which occurs so repeatedly without 

 attention being directed to it, although it can be voluntary restrained 



