DRUGS WHICH ACT ON THE HEART AND BLOOD-VESSELS 459 



Heat is a rapid stimulant when applied to the walls of the chest, or as 

 a hot iluid passed into the stomach; but in the equine patient we have to 

 rely chiefly upon drugs, and of these alcohol, ammonia, ether, and camphor 

 are the chief. 



Ammonia is a gas dissolved in water, but in that condition is not 

 often employed in horse practice. 



The chief preparations are: — ■ 



Strong Liquid Ammonia. 

 Dilute Liquid Ammonia. 

 Aromatic Spirit of Ammonia. 

 Liniment of Ammoin'a. 



Carbonate of Ammonium. 

 Chloride of Ammonium. 

 Acetate of Ammonium. 



Actions and Uses. — Ammonia is a stimulant when applied to the 

 skin, the neutral salts having the least action and the strong liquid the 

 greatest, the latter producing vesicles like an ordinary blister. Weak 

 solutions are used to neutralize the stings of insects, which are usually acid. 

 When inhaled, ammonia rouses the heart and quickens the pulse and 

 respiration. It is employed in this way as a restorative after operations 

 under chloroform when the patient is disposed to remain too long under 

 its influence. The liquid is particularly irritating to the nostrils, and 

 should not be brought into actual contact either with the thin skin 

 covering them or the membrane within. 



Ammonia has a stimulating effect also when passed into the stomach, 

 and the preparations to lie preferred for internal administration are the 

 aromatic spirit (sal volatile), largely diluted, or a solution of the carbonate. 

 In the latter form it not only increases the heart's action, but stimulates 

 the stomach and bowels before it enters the circulation. For this reason it 

 is a valualjle remedy in flatulent colic, and for various forms of indigestion 

 it is prescribed with vegetable tonics. 



It is given in respiratory affections because it stimulates the membranes 

 of the bronchial tubes to expel mucous matter from their surface. The 

 acetate is employed as a febrifuge, and promotes the action of the skin. 



Chloride of ammonium is given in chronic diseases of the liver, and as 

 an external remedy it is used in combination with other drugs as a coolino- 

 or evaporating lotion for inflamed joints and tendons. 



Ether. — This drug has long been a constituent of colic draughts, and 

 is one of the most rapidly diffusible stimulants. Its action upon the heart 

 is very marked, and it is employed in a variety of ways, subcutaneous 

 injection being the most rapid. It is also used as an angesthetic. 



Camphor. — Camphor is a concrete volatile oil obtained by sublimation 

 from the twigs of the camphor tree, which grows in the Dutch Indies, 



