31(5 CALABAR BEAN-OPHTHALMIC t'SK. 



ON THE BEST METHODS OF APPLYING THE 

 CALABAR BEAN IN OPHTHALMIC MEDICINE. 



(Caldbarbohne in dcr Angenheilkunde) 



1863. I HAVE stated that certain difficulties occur in forming a p re- 



Difficulties in paration of the Calabar Bean which can be conveniently applied 

 Ophthalmic to the eye Thege difficulties ar i se f rom t ] ie f act that the 



alcoholic extract, which contains the whole of the poisonous 

 principle of the bean, 1 can only be imperfectly dissolved in 

 water, and that its alcoholic solution is inadmissible. There 

 is also another difficulty which occurs with all liquids that 

 are required to be dropped into the eye, and that is, that the 

 flow of tears which instantly follows such an application 

 gieatly reduces the amount placed in contact with the mem- 

 brane, or at any rate renders it very uncertain. 



These considerations have suggested other expedients for 

 applying the remedy, one of which is to use the extract by 

 itself; another is to employ it diffused through paper, after 

 the manner recommended by Mr. J. F. Streatfeild for the 

 Modes of application of atropine ; 2 and a third is to use a solution of 

 Application. |. e ex t rac t i n glyceiine. Each of these methods has certain 

 advantages. The extract, which is prepared by exhausting the 

 finely -powdered bean with alcohol (sp. gr. '838) and evaporating 

 the solution, is not a homogeneous body, but contains a small 

 amount of greenish fatty oil which separates as the solution is 

 concentrated. Its action upon the eye is rapid and powerful. 

 The best means of using it is to moisten a camel's-hair pencil 

 with water, and then with its tip to rub off a minute quantity 

 of extract and apply it to the palpebral conjunctiva of the 

 lower lid: so applied, its specific action ensues in the course 

 of a few minutes. This method of the direct application of 



1 Since publishing my former paper I have ascertained that the finely 

 powdered bean deprived of everything that alcohol would remove is no 

 longer poisonous to rats. 



2 Ophthalmic Hospital Heport, Jan. 1862, p. 310; also Pharm. Jour,/.. 

 Jan. 1863, p. 329. 



