_Treatment._ In vomiting animals encourage emesis by tepid water, tickling the fauces, or giving ipecacuan. For non-vomiting animals the stomach pump may be tried. The available antidotes are hydrated oxide of iron, or a solution of calcined magnesia. To make the first, mix 100 parts sulphate of iron in solution with 250 parts magnesia in solution. This should be given liberally and often: horse or ox 1 qt., sheep or pig 2 ozs., dog 1 oz. A simple aqueous solution of calcined magnesia also forms with arsenic an insoluble combination. CHRONIC ARSENICAL POISONING. This comes from continuous injudicious dosing with arsenic, or from the condensing on the grass of the vapors from the smelting of ores containing arsenic. _Symptoms._ There is chronic indigestion, emaciation, hide-bound, depilation, red or weeping eyes, chronic diarrhœa, suppression of milk in cows, muscular weakness, paraplegia, soreness of the gums, salivation. The _lesions_ are essentially the same only less intense than in the acute form. Hugo found in the intestines of poisoned animals a slimy, serous, grayish white fluid, and a false membrane like a frog spawn streaking the intestine. Later this may be dense like a diphtheritic membrane. There was fatty degeneration of the liver and of the gall bladder epithelium. Injection of the capillary vessels of the brain and pia, and effusion into the ventricles and on the surface of the brain were found in dogs. _Elimination._ Arsenic is eliminated mainly in the urine, but also in part in the bile and perspiration. _Tests for Arsenic._ When taken in the solid form it may be found undissolved on the gastric mucosa. If burned on red hot charcoal or iron it gives out the odor of garlic. Marsh’s test consists in evolving arseniureted hydrogen from zinc and sulphuric acid to which a little of the suspected liquid has been added. A flask is taken having a cork conveying two tubes, one a funnel reaching nearly the bottom of the flask, and the other a delivery tube of some length and provided with a chloride of calcium bulb, and at its end turned up at right angles and drawn out to form a narrow orifice. Pieces of zinc are placed in the bottom of the flask, and sulphuric acid is poured upon these through the funnel. This causes the evolution of hydrogen. The suspected liquid is now added, and the gas issuing from the delivery tube having been lighted, a piece of cold white porcelain is held above and a short distance from the flame. A dark metallic spot of arsenic is obtained. The stain obtained by antimony differs in being formed more closely to the flame, in volatilizing less rapidly under heat, and in forming a black or orange instead of the canary yellow sulphide when subjected to a stream of H_{2}S. with gentle heat. Chloride of lime dissolves the arsenic stain but has no effect on the antimonial one.