Basing his opinion on previous studies, in particular those of A. Heffter and collaborators in 1903 and 1908,1 P. Ehrlich2 in 1909 stated his idea that the toxic action of arsenic is due to its attack on sulfhydryl (SH) compounds or "arsenoreceptors." These compounds were recognized as essential to biologic oxidation and reduction processes. Many other investigators have advanced the thesis that metallic compounds and certain other poisons combine with the thiol groups of tissue enzymes or of members of oxidation and reduction systems, such as glutathione and cysteine, and thus inactivate these constituents necessary to life and function. Long before World War II the concept was generally held that "detoxification" of arsenic and of certain other metallic and even nonmetallic compounds may be accomplished by administration of chemicals containing thiol groups. One of the early fundamental studies of this effect was that of C. Voegtlin, H. A.
SULZBERGER MB, BAER RL. DEVELOPMENT AND USE OF BALA Review, with Particular Reference to Arsenical Dermatitis. JAMA. 1947;133(5):293–296. doi:10.1001/jama.1947.02880050013002