MAGNESIUM 131 



That the toxic line is closely approached in giving barium chloride 

 in the dose of 2 Gm. intravenously, is shown by experiment 31,* in which 

 a gelding weighing 900 pounds received two 2 Gm. doses intrajugularly 

 at about 2% hours apart, when death occurred from heart failure in nine 

 minutes after the second dose. Barium chloride is useful in relieving 

 tympanites of cattle. 



Four to five drams are given to cattle and one and one-quarter drams 

 to calves in drench. Since writing the above many fatalities have oc- 

 curred from the intravenous injection of barium, so that it has largely 

 gone out of use save by the mouth. Used intravenously it cannot be said 

 to be other than dangerous. In human practice it is not employed on 

 account of its toxicity and irritating effect upon the digestive tract. 



Magnesium, 



(The metal is not used in medicine.) 



Maonesii Sulphas. Magnesium Sulphate. MgSOj + T HjO. 

 (U. S. & B. P.) 



Synonym. — Epsom salt, sal amarum, sal Epsomense, sal anklicum, sulfas 

 magnesicus, etc., E.; magnesium sulfulicum, P. G. ; sulfate de magnesie, sel 

 d'Epsom, sel de seidlitz, sel amer, Fr. ; bittersalz, schwefelsaure magnesia, G. 



Denvation. — It is obtained from native dolomite, a double carbonate of mag- 

 nesium and calcium, or magnesite (MgCOg). MgCOs-j-H^SOi = MgSOi-J-HjO-l- 

 COj. 



Properties. — Small, colorless, prismatic needles or rhombic prisms, without 

 odor, and having a cooling, saline and bitter taste; slowly efflorescent in the 

 air ; soluble in one part of water ; almost insoluble in alcohol ; reaction neutral. 



Incompatibles. — Lime water, alkaline carbonates, phosphoric acid, phosphates, 

 silver nitrate and lead acetate. 



Dose. — H., laxative, Sii-iv, (60-120) ; C, purgative, Ibi-ii, (500-1,000) ; laxa- 

 tive 5iii-iv, (90-120); Calves, oil-iii, (60-90); Sh., giv-vi, (120-180); D., 3i-iv, 

 (4-16). 



Action Internal. — Epsom and Glauber's salts are the best purgatives 

 for general purposes in the treatment of cattle and sheep. The mode of 

 action of Epsom salt is similar to that described under sodium sulphate. 

 Briefly, magnesium sulphate causes purgation by increasing intestinal 

 secretion, retarding absorption of fluid from the bowels, and by slightly 

 stimulating peristalsis. The salt moves the bowels, in the case of the 

 larger animals, usually within twelve or fifteen hours. 



Epsom salt is absorbed to some extent, and is eliminated by the kid- 

 neys and sweat glands, increasing the secretions of these organs, espe- 

 cially when the dose is small. 



Summary. — Hydragogue cathartic. Feeble diuretic and diaphoretic. 



Uses. — For uses the reader is referred to sodium sulphate (p. 113), 

 as the uses of the two salts are almost identical. Epsom salt is useful 

 in febrile diseases of horses, as in infiuenza and pneumonia, given in 

 solution, in doses of two to four ounces twice daily. Solutions of mag- 

 nesium sulphate produce local anesthesia when injected under the skin 

 or intraspinally. 



*Jour. of Comp. Med. and Vet. Archives, Jan. and Feb., 1899. 



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