AGENTS ACTING UPON THE RECTUM 257 



_ 2. In pharyngitis and tetanus it is contraindicated because the 

 animal swallows with difBculty and may even smother in its own 

 saliva. 



Arecoline Hydrobromide. This agent combines the action of 

 the two preceding drugs. 



Therapeutics, l. Similar to the preceding for action on the 

 bowels. 



2. A specific for acute laminitis. 



These drugs are administered hypodermically in most cases. 

 Small doses may he given per os to small animals. 



Barium Chloride. 



This is a rapid purgative when given by mouth, and the most 

 rapid of all purgatives when administered intravenously. It should 

 not' be given subcutaneously since it will form an abscess. Barium 

 chloride is an intense irritant to the muscular system in general and 

 to the gastro-intestinal tract. It will cause purgation in horses in 

 one-half to an hour after administration in a drench ; in one to two 

 hours if administered in ball; and within a few minutes following 

 intravenous administration. It has been recommended as a rapid- 

 acting cathartic for horses in doses of lYz to 15 grains (.5 — 1.) 

 intravenously, and is the most rapid purgative known. It is be- 

 lieved that its purgative action following intravenous administration 

 is due to its excretion in the intestines, which it irritates and thus 

 causes increased peristalsis. A great many fatal results have fol- 

 lowed the administration of this drug in such large doses and its use 

 has been quite largely abandoned. Small or fractional doses are still 

 tised by some practitioners. In doses of one to two drams (4. — 8.) 

 per OS barium chloride is followed by good results according to 

 some practitioners. For more details of its action see Barium 

 p. 357. 



AGENTS ACTING UPON THE RECTUM 



Enemata. These are rectal injections and may be employed 

 for cathartiCj nutritive or cleansing purposes. Furthermore, they 

 may be used to expel gas or to carry remedies to the mucous mem- 

 brane of the rectum and possibly colon in some animals. 



The cathartic enemata may be further divided into softening 

 agents for the feces and as purgatives. 



The softening agents are water, soapsuds, glycerin, ox gall and 

 olive oil. Hertz concluded that water was superior to olive oil, 

 equal to ox gall, and that glycerin increased the penetration of the 

 water. The best softening enema is probably normal saline solution 

 500, and glycerin 15. (1 pint — % oz.). 



The purgative enemata act either by irritating the rectum, or by 

 mechanical means. The former consists of small amounts of fluid 

 which contain aloes or some other irritant purgative, while the latter 



