wound in the back of a rabbit,—the convulsions being preceded by palsy, and ending in coma. Half an ounce when injected into the stomach excited the same symptoms in a cat, and proved fatal in sixty-five minutes, though the animal vomited. Schloepfer observed, that when a scruple, dissolved in two drachms of water, was injected into the windpipe of a rabbit, it fell down immediately, threw back its head, was convulsed in the fore-legs, and died in twelve minutes.[1] Gmelin observed in his experiments that it caused slight inflammation of the stomach, and strong symptoms of an action on the brain, spine, and voluntary muscles. He found the voluntary muscles destitute of contractility immediately after death; yet the heart continued to contract vigorously for some time, even without the application of any stimulus. From some experiments made on horses by Huzard and Biron, by order of the Société de Santé of Paris, it appears that the hydrochlorate, when given to these animals in the dose of two drachms daily, produced sudden death about the fifteenth day, without previous symptoms of any consequence.[2] In the experiments now related, very little appearance of inflammation was found in the parts to which the poison was directly applied. It is also worthy of remark that the heart does not seem to have been particularly affected; and yet according to the recent researches of Mr. Blake, the barytic salts are the most powerful of all inorganic poisons in their action on the heart, when they are injected into the veins. A quarter of a grain of the chloride appreciably depresses arterial action; two grains completely arrest the heart's contractions in twelve seconds; and when it is injected back into the aorta from the axillary artery, it causes at first some obstruction to the capillary circulation, but soon arrests the action of the heart, as when it is introduced into the veins.[3]
The pure earth appears to produce nearly the same effects in an inferior dose. When swallowed, the symptoms of local irritation are more violent; but death ensues in a very short space of time, and is preceded by convulsions and insensibility. The stomach after death is found of a reddish-black colour, and frequently with spots of extravasated blood in its villous coat.
The carbonate in a state of minute division is scarcely less active than the hydrochlorate, since it is dissolved by the acid juices of the stomach. A drachm killed a dog in six hours; vomiting, expressions of pain, and an approach to insensibility preceded death; and marks of inflammation were found in the stomach.[4] Pelletier made many experiments on the poisonous properties of the carbonate. Fifteen grains of the native carbonate killed one dog in eight hours, and another in fifteen.[5] Dr. Campbell found it to be a dangerous poison, even when applied externally. Twelve grains introduced into a wound in the neck of a cat, excited on the third day languor, slow respiration, and feeble pulse; towards evening the animal became affected with convulsions of the hind-legs and with dilated
