24 SYNOPSIS OF V^TERINARV 



and the mechanical expulsion of mucus. They also increase 

 secretion, generally, and lower blood pressure. 



Stimulant Expectorants. — Are eliminated from the system 

 largely by the bronchial' mucous membrane which they at the 

 same time stimulate, thus altering its secretion and facilitating 

 expectoration. They diminish secretion generally, and increase 

 the blood pressure ; they include the ammonia salts, benzoin, am- 

 moniac, squills, etc. 



Respiratory Stimulants. — Exalt the function of the respira- 

 tory centers in the medulla, quickening and deepening the breath- 

 ing, as strychnine, atropine, digitalis, ammonia, thebaine, etc. 



Respiratory Depressants. — Lower the action of the respira- 

 tory center, rendering the respirations slow and shallow. 



They are chiefly opium, in full doses; gelsemium, aconite, 

 veratrum, conium., chloral, ether, etc. 



Pulmonary Sedatives. — Relieve cough and dyspnoea by less- 

 ening the irritability, either of the respiratory center or of the 

 nerves of respiration. 



Some act by direct depression of the respiratory center, as 

 the depressants above named, others by lessening local conges- 

 tion, as the expectorants, and others by lowering the excitability 

 of the vagus end organs in the lungs, and other nerve filaments 

 throughout the respiratory tract. 



Such are opium, hydrocyanic acid, belladonna, cannabis in- 

 dica, etc. 



AGENTS ACTING ON THE CIRCULATION. 



Cardiac Stimulants. — Rapidly increase the force and fre- 

 quency of the pulse in depressed conditions of the heart ; alcohol 

 and ether stimulate the motor ganglia, physostigmine and cam- 

 phor, acting chiefly on the heart muscle. 



Aq. ammonia, carbonate of ammonia, spts. ammonia aro- 

 maticus, chiefly stimulate the vaso-motor centers. 



Other stimulants are atropine, belladonna, morphine in small 

 doses, chloroform, turpentine, aromatic oils, counter-irritation, 

 nitro-glycerin, strophanthus, digitalis and electricity. 



Cardiac Tonics.- — Act slower than stimulants, increase the 

 vigor of the heart muscle, slowing and lengthening the contrac- 



