1885.] produced by the Application of Cocaine to the Eye. 437 



Brown and White Rabbit. — Pupils 7' 5 mm. X 6 mm.; right cervical 

 sympathetic exposed and cut, very slight change in pupil ; animal 

 bled to death from ascending aorta in two minutes ; pupils after 

 death, right 7'5 mm,, left 9*5 mm. ; right sympathetic irritated by 

 current, and pupil 10*5 mm. ; 10.53, cocaine 4 per cent, twice to both 

 eyes ; 11.7, right eye pupil 9 mm., left eye pupil 10*5 mm. 



In several experiments on the influence of cocaitie on the mydriatic 

 nerve which is to be found in the sympathetic accompanying the 

 carotid in the neck, the following were the chief results : — 



Experiment XIV. 



On exposing the cervical sympathetic as it runs in proximity to the 

 common carotid, cutting it and adding cocaine, dilatation of the pupil 

 occurred in all cases, but less than the ordinary cocaine mydriasis, and 

 in the first case scarcely at all. 



I. Black Rabbit. — Pupils regular, equal, 6"5 mm. under chloroform ; 

 left sympathetic exposed, ligatured, cut, followed by slight contraction 

 of pupil, and injection of vessels of ear, &c. The upper end of the 

 nerve stimulated by weak faradaic current, and pupil 10 mm. 



Right eye pupil 6'5 mm., left eye pupil 5*5 mm. ; 10 a.m., cocaine 

 2 per cent, in both eyes; 10.8 a.m., right eye pupil 8*5 mnu, left eye 

 pupil 6 mm. 



Cocaine 2 per cent, twice more in each eye ; 11 a.m., right eye pupil 

 9*5 mm., left eye pupil 6*5 mm. 



II. White Rabbit. — Pupils regular, equal, 6*5 mm. under chloroform ; 

 right sympathetic exposed, ligatured, cut; pupil afterwards 5'5 mm. 

 On stimulation by weak faradaic current, pupil 10 mm.; 12.54 p.m., 

 right eye pupil = 5 - 5 mm., left eye pupil 6*5 mm. Cocaine 2 per 

 cent, twice on conjunctiva on each eye; 1.18, right eye 8 mm., left 

 eye 9 mm. ; 1.30, right eye 8 mm., left eye 10 mm. 



Experiment XV. 



On adding cocaine and producing mydriasis, subsequent section of 

 the cervical sympathetic had no effect on the mydriasis, even when an 

 ad maximum dilatation was produced. 



Brown and White Rabbit. — Pupils 5 mm. X 6 mm. under chloro- 

 form ; 10.35 a.m., left eye, cocaine 2 per cent. ; 10.55 a.m., after three 

 instillations of cocaine, left pupil 8 mm. X 7 mm. ; 11.20, after five 

 instillations of cocaine, left pupil 10 mm. 



Left cervical sympathetic exposed, cut, and no effect followed on 

 pupil, though all other symptoms of cutting the nerve. 



Experiment XVI. 



Cocaine mydriasis being produced, stimulation of the upper end of 



2 I 2 



