Baryta, and its Salts.
Baryta, like lime, is a solid, heavy, alkaline earth, having an acrid and peculiar taste; and turning the syrup of violets green, and the juice of turmeric red. When perfectly calcined, it absorbs water very rapidly, disengaging at the same time a quantity of caloric; the phenomenon is similar to that of slacking lime, and admits of the same explanation. It dissolves in about 20 parts of water, at the temperature of 60°; but boiling water will dissolve half its weight of this earth, part of which will crystallize on cooling.
Muriate of Baryta. This salt crystallises in square plates, or four-sided prisms; its taste is acrid and pungent. It dissolves in 2½ parts of distilled water at 60° Fah. The solution is limpid and colourless, and has been employed in medicine, as a remedy in scrofula, cancer, some forms of syphilis, and in hectic fever connected with ulceration. Dr. Johnstone says that he has seen a delicate female take as much as thirty drops of a saturated solution of this salt, repeatedly, without nausea; whence he concludes that it would require at least 2 or 3 drachms to do mischief.[[333]]
Symptoms of poisoning by Baryta.
All the soluble compounds of this earth are poisonous, especially the muriate; which, whether injected into the veins, introduced into the stomach, or externally applied to an abraded surface, will occasion death in a very short period. We are not aware that any case stands recorded of poisoning by baryta. Orfila[[334]] and Brodie[[335]] have, however, investigated the symptoms which this poison produces on animals, and they appear to be analogous to those occasioned by the ingestion of arsenic. The muriate, on account of its greater solubility, would appear to be much more active than the pure earth, or its carbonate.
Physiological action of Baryta.
Barytic poisons require to be absorbed before they act on the system; they may therefore destroy by external application, although it would appear that, unlike arsenic, they act sooner when internally administered. Mr. Brodie thinks that the muriate of baryta occasions death by acting upon the brain and the heart; at the same time it exerts a local action, and corrodes the viscus with which it comes into contact.
Antidotes.
It has been shewn by the experiments of Orfila, that the soluble sulphates, as Glauber or Epsom salts, by converting the baryta into an insoluble sulphate, will act as antidotes to its virulence. In the first instance, therefore, it will be prudent to produce this chemical decomposition in the poison, and then to expel it, as quickly as possible, by emetics.