92 EXPECTORANTS 



membrane, or when the secretion becomes thick and ad- 

 hesive, so that irritating coughing is set up, expectorants 

 increasing secretion and assisting its expulsion are indicated. 

 They may produce their action in various ways. Some 

 agents, such as jaborandi and pilocarpine, stimulate the 

 secretory nerve-endings in the mucous glands and so in- 

 crease secretion. Others are absorbed into the system and 

 excreted to a greater or less extent by the bronchial mucous 

 membrane, and their local effect is to increase secretion. 

 Such are the alkaline carbonates and the iodides. Still 

 another class are drugs which are irritants in the stomach 

 and produce vomiting in larger doses, such as ipecacuanha, 

 saponins, tartar emetic, and squill. These in small doses 

 all increase bronchial secretion. Then in addition to the 

 foregoing are the balsams and volatile oils, which, besides 

 being partly excreted in, and increasing, bronchial secretion, 

 also exert antiseptic effects locally. Terpine, oil of turpen- 

 tine in a vaporised state, creosote, or the old popular remedy 

 of the fumes of burning tar, prove effectual in moderating 

 irritable congestion and continued secretion in many cases of 

 bronchitis by their disinfectant action, and by causing expul- 

 sion of the irritant. A relaxed throat generally indicates the 

 existence of a similar condition throughout the respiratory 

 tract. An appropriate remedy is a combination of terebene 

 and an acid given as an electuary, which exerts beneficial 

 effects both topically and generally. 



Expulsion of the respiratory secretions is produced by in- 

 creased activity of the cilia, which are believed to be stimu- 

 lated by ammonia solutions ; by coughing ; and by in- 

 creased activity of the respiratory centre, which, as already 

 stated, is stimulated by ammonia salts, as well as by ipeca- 

 cuanha, belladonna, and strychnine. 



Influenza colds, so common amongst horses, and notori- 

 ously infectious, no doubt depend upon specific micro- 

 organisms, which attack the upper, sometimes the lower 

 air-passages, and not infrequently also induce gastro-intesti- 

 nal catarrh, and other complications. Occasionally such 

 seizures may be checked or mitigated in their early stages by 

 moistening the parts first affected with solution of carbolic 

 or sulphurous acid or eucalyptus oil, applied in the form of 



