Biological interaction of selenium with other trace elements in chicks.

Studies were conducted to determine whether or not elements whose valence shell of electrons was similar to that of selenium would reverse the toxicity of selenium to chicks. The elements studied were arsenic, tellurium, tin, and lead. Each of these elements, when added to the diet of chicks, reversed the toxicity of 25 ppm selenium as measured by weight gain. In spite of the protection afforded by these elements, there was no decrease in liver concentration of selenium except with levels of arsenic higher than that needed for reversal of toxicity.