BAEIUM 161 



puTging. Evacuations from the bowels follow in horses 

 one-half to one hour after the salt is given in drench ; in one 

 to two hours after administration to these animals in hall; 

 in a few minutes after intravenous injection. Subcutaneous 

 application will occasion abscess. The drug resembles 

 physostigmine in its action on the intestines. 



Heart and Blood Vessels. — Barium chloride makes the 

 ventricular contractions of the heart stronger and slower. 

 The salt acts entirely on the heart muscle and does not 

 influence the vagi. Lethal doses are followed by slower and 

 slower ventricular contractions, succeeded by peristalsis of 

 the cardiac muscle, and, finally, by stoppage of the heart in 

 systole. 



Barium chloride also directly excites the muscular walls 

 of the capillaries, and, like physostigmine, increases vascular 

 tension in small doses. 



Muscles. — Barium chloride stimulates muscular con- 

 traction when it is applied locally. The potassium salts 

 antagonize the action of barium chloride on the circulation 

 and muscles. Toxic doses, given intravenously, cause con- 

 vulsions owing to stimulation of the spinal cord and medulla. 

 This is succeeded by paralysis of the central nervous system. 



Summary. — Circulatory stimulant, and purgative in 

 large medicinal doses. 



Uses. — Barium chloride is a new remedy in veterinary 

 medicine. Many practitioners are afraid to use barium 

 chloride, but repeated use of the drug has convinced us that 

 it is absolutely safe when given in the dose of 1 gram or 15 

 grains, intravenously, or 8 to 15 grams (2 to 4 drachms) by 

 the mouth in solution for the horse. The intravenous dose 

 of 1 gram, or the dose per orem of 8 grams, may be repeated 

 with safety in one hour if necessary. Barium chloride is of 

 the greatest value in colic and obstinate constipation of 

 horses. It may for the time cause some increase of pain, 

 but not nearly as much as follows the use of eserine or 

 arecoline, and it quickly passes off when the bowels are 

 moved. Great care should be exercised to avoid introduc- 

 tion of the barium solution into the connective tissue while 

 injecting it into the vein. The needle of the hypodermic 



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