1885.] produced by the Application of Cocaine to the Eye. 435 



solutions of each drug, and mixing them in the proportion of 25—28 

 of cocaine and 1 of eserine, the normal size of the pupil was un- 

 changed. 



J. Gr., 22. Pupils regular, equal, 6 mm. ; 4 instillations of solution 

 of cocaine and eserine (27 : 1) in right eye. Pupil afterwards regular, 

 6 mm. 



Experiment V. — Cocaine and Pilocarpine. 



The action of pilocarpine was to induce myosis easily. 



On trying mixtures of the drugs I found that 4 of cocaine and 1 of 

 pilocarpine, each 2 per cent, solution, had no effect on the normal 

 pupil. 



A. W., 23. Pupils regular, equal, 5 mm., left eye pilocarpine, 2 per 

 cent, on conjunctiva, bringing pupil to 2*5 mm. ; 4 instillations of 

 cocaine, 2 per cent., brought back pupil to 5 mm. 



J. B., 30. Pupils regular, equal, 5 mm. ; ,3 instillations of cocaine 

 and pilocarpine (4:1) had no effect on pupils. 



The importance of these combinations I have utilised, especially 

 that of pilocarpine and cocaine, for keeping the pupil a normal size 

 during the operation of iridectomy, when anaesthesia has to be induced 

 by cocaine. The objection to the dilated pupil is that it keeps dilated 

 both during and after the operation, and so may become prolapsed 

 afterwards, especially in glaucoma cases ; also if a tolerably large con- 

 junctival flap has been made the iris may disappear under it, and so 

 become difficult to catch hold of, if iridectomy is to be performed. 

 This combination does not prevent the local anaBsthesia of cocaine. 

 The antagonism between eserine and pilocarpine on the one hand, and 

 cocaine on the other, gives us a means of estimating the relative 

 power of pilocarpine and eserine on the pupil. 



Experiment VI. 



Cocaine increases the mydriasis produced by section of the 3rd 

 nerve. 



Experiment VII. 



The effect of section of the 3rd nerve on a pupil dilated by cocaine 

 stops its action to light and accommodation, but does not increase the 

 size of the pupil. 



Experiment VIII. 



On stimulation of the 3rd nerve the mydriasis induced by cocaine 

 easily and quickly gives place to myosis. 



A. B., 29, suffering evidently from syphilitic mischief, probably 

 gummatous, implicating the right 3rd nerve, and producing complete 

 ptosis, external strabismus, inability to move the eye up, down, or in, 

 diplopia, loss of accommodation and mydriasis. 



VOL. xxxviii. 2 I 



