Brain tissue reaction to some chronically implanted metals

✓ The toxicity of certain metals, namely, platinum, platinum-8% tungsten, platinum-10% rhodium, platinum-10% iridium, platinum-10% nickel, platinized platinum, a gold-nickel-chromium alloy, a gold-palladium-rhodium alloy, a chromium-nickel-molybdenum alloy (Vitallium), stainless steel, silver, rhenium, and gold, was evaluated histologically following chronic implantation for 2 months in the brains of cats. Of the above metals, all but silver were found to be nontoxic. Boron was also evaluated and found to be nontoxic.