DEUGS WHICH ACT ON THE DIGESTIVE SYSTEM 467 



destroy certain classes of worms. Where a large dose is desirable the 

 extract may be dissolved or given as a ball. Quassia is more irritating 

 than any of the tonics previously mentioned, and does not suit all 

 cases, but is used a good deal in large studs, where economy is a o-reat 

 consideration. 



Cardamoms have a mildly tonic and stimulating effect upon the 

 stomach, but are not much employed in equine medicines, as they are 

 not only expensive but inferior to gentian, calumba, and quassia as tonics, 

 and might with equal propriety be considered among those drugs called 

 cai'minatives. 



Hops. — As a veterinary drug, this valuable remedy has received 

 inadequate attention at the hands of practitioners. As a stimulant to 

 appetite it is not surpassed by gentian or any of the other drugs previou.sly 

 named. Where a restless watchfulness and irritability supervenes on such 

 debilitating diseases as influenza, hops may be recommended as havino- 

 a sedative influence upon the nervous system. 



Cinchona or Peruvian Bark has been mentioned in connection with 

 its chief alkaloid, quinine. 



Acid Tonics.— " Acid Tonics" and the "mineral acids" are fre- 

 quently referred to in other parts of this work treating of disease. They 

 are an important class of remedies, and the chief of them in use for horse 

 ailments are the following : — 



o 



Dilute Hydrochloric Acid, 



„ Nitric Acid, 



„ Nitro-hydrochloric Acid, 



„ Phosphoric Acid, 



„ Sulphuric Acid, 



,, Sulphurous Acid. 



Uses of Acids. — It will be inferred from previous references to 

 digestion and digestive troubles that acids similar to those normally 

 secreted will prove valuable when Nature's laboratory fails to produce 

 them in suflicient quality or quantity. In the use of acids as an aid to 

 digestion two factors should be borne in mind, viz., while acids increase 

 the dissolving or digesting jjower of the gastric juice when food is in the 

 stomach, they have the effect upon an empty stomach of retarding the 

 secretion of natural acid; they should always therefore be given imme- 

 diately after food and not before a meal. The seeming contradiction of 

 givmg alkalis in some cases where acid .secretion is defective, is exiDlained 

 by the fact that those remedies excite activity on the part of the acid- 

 forming glands. The converse effect is observed upon glands which pro- 

 duce an alkaline fluid, they being stimulated to action by acids, and 



