20 VETERINARY MATERIA MEDICA. 



General Sedatives, which act by reducing irri- 

 tability of the vomiting centre in the medulla— as 

 amyl nitrite, chloral, bromides, hydrocyanic acid, 

 and nitroglycerin. 



Carminatives favor the expulsion of gases from 

 the stomach and intestines by stimulating peristalsis 

 and the circulation — as asafcetida, capsicum, fennel, 

 camphor, ginger, mustard, pepper, and most of the 

 aromatic oils. 



Cathartics or Purgatives are agents which in- 

 crease or hasten the intestinal evacuations. They ^re 

 divided into several groups, according to degrees and 

 modes of action : Laxatives or aperients, simple pur- 

 gatives, drastic purgatives, saline purgatives, hydra- 

 gogue purgatives, cholagogue purgatives. 



1. Laxatives or Aperients, whose action is only 

 moderate — as sulphur, magnesia. 



2. Simple Purgatives, which cause active peri- 

 stalsis and . some irritation and griping. These in- 

 clude aloes, linseed oil, castor oil, rhubarb, calomel, 

 and senna. 



3. Drastic Purgatives act still more powerfully 

 than the simple purgatives. They cause large watery 

 evacuations, with considerable griping and tenesmus. 

 The chief members of this group are croton oil, gam- 

 boge, scammony, elaterium, colocynth, and jalap. 



4. Saline Purgatives increase peristalsis, pro- 

 mote osmosis, stimulate the glands, and thus produce 

 free watery evacuations. These include Epsom salt, 

 Glauber salt, chloride of sodium, etc. 



5. Hydragogue Purgatives are the most active 



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