STOMACHICS. 407 



Equally powerful is the influence of many substances and 

 measures, as gastric sedatives, in reducing the sensibility of the 

 afferent nerves, and thus interfering with gastric sensations, 

 and the gastric functions which depend upon the reflection of 

 impressions. Opium is thus all-powerful in preventing or re- 

 lieving pain in the stomach, and in arresting the gastric secre- 

 tions and movements. Diluted Hydrocyanic Acid and Bella- 

 donna and its allies, also act in this way ; as well as Carbonic 

 Acid in the form of effervescence ; and water, either as hot as it 

 can be drunk or in the form of ice. Bismuth, whether considered 

 mechanically or physiologically is uncertain ; and Oxalate of 

 Cerium is in a manner still obscure. A number of drugs remove 

 causes of irritation, and are thus gastric sedatives, such as Oxide 

 of Silver, Creasote, and Carbolic Acid, which arrest disorder of 

 the mucous membrane. Various applications to the epigastrium, 

 including poultices, fomentations, and blisters, afford a con- 

 venient means of soothing the gastric nerves reflexly through 

 the nervous centres. 



4. The circulation in the stomach is also so far under our 

 control, as we have already seen. The many substances which 

 stimulate the nerves also redden the surface of the mucous 

 membrane, by dilating the vessels and increasing the local blood 

 flow within physiological limits, such as Alcohol, Ether, 

 Aromatic and Pungent articles (Pepper, Mustard, Capsicum, 

 etc.), and Bitters. Besides these, there are numerous substances 

 of a more powerfully irritant nature which we note chiefly 

 for the purpose of suggesting caution in their employment for 

 other purposes. Arsenic, Iron, Mercury, and indeed the salts of 

 most of the metals : Senega, Digitalis, and Scilla ; Colchicum 

 and Veratria, are examples of drugs which are specially apt to 

 derange digestion. On the other hand, the local circulation can 

 be rendered less active by means of Acids; salts of Silver, 

 Zinc, Lead, in small doses ; Ergot, Opium, Tannic Acid, and 

 the many vegetable astringents containing it, such as Kino, 

 Catechu, and Cinnamon. These are gastric astringents, and 

 indirectly, therefore, another class of gastric sedatives. 



5. The movements of the stomach can be readily modified. 

 The energy of the churning movements increases with the 

 acidity of the chyme, and we can take advantage of this know- 

 ledge by administering acids after meals, such as Diluted Nitric, 

 Hydrochloric, or Nitrohydrochloric Acids, which are thus 

 another class of gastric stimulants, sometimes called gastric or 

 stomachic tonics. Specific nervo-muscular stimulants, such as 

 Strychnia, probably act in the same way, as well as the 

 stimulants of the nerves and vessels, especially Ether and 

 Volatile Oils. That powerful excitation of the movements of 



