MINERAL OE INOKGANIC POISONS 67 



formation. Barium is, however, stated to be deposited 

 in the bones in barium poisoning. Of the salts, the 

 sulphate, or heavy spar, is insoluble both in water and aeids, 

 and is consequently inactive. The carbonate is soluble in 

 hydrochloric acid and is therefore converted into the 

 chloride in the acid stomach. It is used as a component of 

 some arsenical rat powders. The nitrate and chlorate are 

 both soluble, and are used to make green fires in ;pyro- 

 techny. The chromate is used as a yellow pigment, and 

 barium also finds a limited application in glass making. 

 By reason of the great density of the barium compounds, 

 the sulphate is sometimes used to bulk fabrics, and has 

 been found in the coatings of cheeses. But there is no 

 ground for regarding this as likely to cause poisoning. In 

 veterinary therapeutics barium chloride is given intra- 

 venously in 8 to 20 grain doses to the horse, or 1| to 2 or 

 even 3 drachms by the mouth, and 75-gramme drenches 

 to cattle. It is employed in impaction of the colon, and 

 causes violent contraction of the intestine. 



Toxic Doses. — Sixty grains prove poisonous to dogs, and 

 horses have been killed by five daily doses of 75 grains of 

 the chloride. These isolated examples -must be taken with 

 reserve. By injection far smaller amounts are dangerous. 



Symptoms. — When concentrated, the barium salts act as 

 irritapts, but are not easily absorbed from the alimentary 

 tract. By whatever channel given, barium acts as a powerful 

 purge, and when possible causes vomiting. There is stag- 

 gering, loss of control of movements, and difficulty in 

 standing. 



Barium acts on the heart like digitalis, the ventricular 

 contractions being slowed, and the heart eventually arrested 

 in systole. Given intravenously, barium causes clonic and 

 tonic convulsions, and the same general symptoms of vomi- 

 tion and purging. 



Post-MoFtem Appearances are not characteristic. Some 

 inflammation of the stomach is seen after large doses of the 

 soluble salts. Congestion of the lungs, kidneys, and brain 

 ■will be observed. 



