PURGATIVES RELIEVE PYREXIA 113 



and one or two grains of pilocarpine ; or by intravenous 

 injection of a solution of barium chloride, or arecoline 

 hydrobromide. Constipation, troublesome in dogs kept 

 in the house, or on the chain, is best treated with a dose 

 of oil, and prevented by attention to diet. 



Diarrhoea, at its outset, is usually most effectually treated 

 by a dose of oil, containing a little laudanum or hyoscyamus 

 a combination which removes the cause of irritation, and 

 prevents irregular peristalsis and griping. 



(2) Purgatives, notably salines or hydragogues, increase 

 the amount of intestinal fluid, hinder its absorption, and 

 thus purge the blood of waste products, relieving febrile 

 attacks, and lowering blood-pressure. 



The blood, thus left in a state of concentration, speedily 

 recuperates itself, absorbs water and lymph from the tissues, 

 thus relieving oedema, dropsy, and lymphangitis. To secure 

 this special action, such salines as Epsom salt and alkaline 

 tartrates are specially useful, and their efficacy is increased 

 when they are prescribed in tolerably concentrated form, 

 and given when there is comparatively little fluid in the 

 alimentary canal. 



(3) Purgatives lower fever temperature, but how this 

 effect is produced is not definitely known. They diminish 

 the force of the circulation, and may in this way lessen the 

 production of heat, and, moreover, hasten removal from the 

 body of waste or other deleterious matters, which are a fre- 

 quent cause of fever. In animals in health purgatives do not, 

 however, produce any appreciable lowering of temperature. 



CARMINATIVES are agents which regulate peristalsis and 

 assist the expulsion of gases from the stomach and intestines. 

 When digestion is in any way interfered with, the contents 

 of the stomach are liable to undergo excessive or irregular 

 fermentation, giving rise to large quantities of gas composed 

 chiefly of carbon dioxide, marsh gas, and hydrogen, with 

 some sulphuretted hydrogen. Formation of these gases is 

 favoured by accumulation of mucus on the walls of the 

 stomach, which prevents secretion of gastric juice, and by 

 want of the normal stomach movements. These gases 

 cause uncomfortable distension, and often provoke spasm 

 and pain. (See Antispasmodics.) 



H 



