INTRODUCTION". 15 



The principal mydriatic, atroxtine, will act both lo- 

 cally as well as internally. 



Myotics are agents which cause contraction of 

 the pupil of the eye — as eserine, pilocarpine, and mor- 

 phine. 



Ocular Sensibility is increased by strychnine, 

 while impairment of vision (amblyopia) due to nerve 

 changes may be temporarily induced by quinine; 

 it may be permanent when caused by lead-poisoning 

 or urea-poisoning. 



Excitability of the Auditory ISTerve is in- 

 creased by strychnine and morphine, which render 

 the sense of hearing more acute; while quinine, sali- 

 cin, and antipyrine produce hypersemia of the audi- 

 tory apparatus, and cause humming or buzzing 

 sounds with diminished sense of hearing. 



The Sense of Smell is rendered more acute by 

 strychnine, and depressed by all of the cerebral de- 

 pressants. 



Agents Acting on Respiratory Apparatus. 



Respiratory Stimulants exalt the function of 

 the respiratory centres in the medulla, which make 

 the respirations quicker and deeper — as strychnine, 

 digitalis, ammonia, ether. 



Respiratory Depressants lower the action of the 

 respiratory centre, rendering the respirations slow and 

 shallow — as opium in full doses, golsemium, aconite, 

 veratrine, conium, and chloral. 



Pulmonary Sedatives relieve cough and dysp- 



