142 GENERAL THERAPEUTICS FOR VETERINARIANS 



and of the lens, detachment of the retina and other internal eye 

 diseases are more readily recognized. 



Drugs. — 1. Atropinae sulphas. The most frequently used 

 mydriatic in periodic ophthalmia, iritis and in operations on the 

 eye; 1 to 2 per cent, solution. For diagnostic purposes a weaker 

 solution is used (J^ to 1 per cent.). 



2. Hyoscinae hydrobromidum. A more powerful mydriatic; 

 therefore used when atropine does not sufl5ce; solution, 0,2 to 0.5 

 per cent. 



3. Homatropinae hydrobromidum. A mydriatic used for diag- 

 nostic purposes. The pupillary dilation disappears more rapidly 

 than when produced by atropine or hyoscine, but occurs much 

 more slowly. Very expensive. 



Newer mydriatics are *mydrol, *mydrin, *eumydrin and 

 *euphthalmiae (very expensive). 



2. PUPIL-CONTRACTING REMEDIES. MYOTICS 



Actions and Uses. — The myotics, of which arecoline and pilo- 

 carpine may be mentioned as the most important, cause a narrow- 

 ing of the pupil by contraction of the sphincter muscle of the pupil, 

 the latter action resulting in consequence of stimulation of the 

 oculomotor nerve. Myosis is of value therapeutically because by 

 the contraction of the iris synechia of the latter with the capsule 

 of the lens will be loosened. Adhesions of the iris occurring in 

 periodic ophthalmia, for instance, are treated alternately with 

 atropine (mydriasis) and eserine (myosis). Eserine is also em- 

 ployed to reduce the internal pressure of the eye in glaucoma. 



Drugs. — 1. Physostigminae sulphas. Eserine. A myotic in 

 synechia of the iris, periodic ophthalmia, adhesion of the iris and 

 prolapse of the iris; 3^ to 1 per cent, solution. 



2. *Arecolinae hydrobromidum. Used in the same manner as 

 physostigmine. 



