Sheet lead—tea-chest lead—is another common source of the poison. This is thrown out, scattered with the manure on the field, and will resist the elements for years but dissolves when taken into the acid stomach of the animal. The spray from bullets in the vicinity of rifle butts is another common cause of the poisoning. In one instance I have seen a cow poisoned by eating some lead-impregnated wall paper which had been carelessly left in the stable. Less frequently the poisoning comes from drinking water carried in leaden pipes, or left to stand in a leaden cistern. The softest waters—rain, snow, distilled water—are the most liable to this impregnation. The hard waters containing carbonates, sulphates or phosphates, tend to be decomposed, the acid uniting with the lead to form comparatively insoluble carbonates, sulphates or phosphates of lead, which protect the subjacent lead against solution. The hardness of the water is not, however, a sufficient safeguard, as iron, solder, and other agents present in the lead as an impurity or merely resting upon it, are sufficient to set up a galvanic action resulting in solution. The salts of lead may find direct access to the animal, as in the case reported by Gamgee in which a farmer used a barrel which had contained acetate of lead for mixing the feed given to his stock. A somewhat similar source of poisoning is found in the use of buckets or silos which have been painted inside, and scale off in contact with hot water, etc. Blythe enumerates the following compounds of lead as employed in the arts: 1st. Hair dyes which have a basis of litharge, acetate or carbonate of lead in combination with lime and other agents. 2nd. White lead in its various forms is carbonate of lead. 3rd. Newcastle white is white lead made with molasses vinegar. 4th. Nottingham white is white lead made with sour ale. 5th. Miniature Painter’s white is lead sulphate. 6th. Pattison white is an oxychloride of lead. 7th. Chrome Yellow is impure chromate of lead. 8th. Turner’s Yellow, Casella Yellow, Patent Yellow is oxychloride of lead. 9th. Chrome Red is a bichromate of lead. 10th. Red Lead is the red oxide of lead. 11th. Orange Red is an oxide obtained by calcining the carbonate. 12th. Nitrate of Lead is much used in calico printing. 13th. Pyrolignite of Lead is an impure acetate used in dyeing. 14th. Sulphate of Lead is a by product in the preparation of acetate of aluminium for dyeing. _Forms._ Lead poisoning occurs in acute and chronic forms. The two forms, however, merge into each other and are largely convulsive and paralytic.