The use of iodides has been the standard form of therapy for the deep mycoses during the past half century. It has withstood well the test of time, not because it was remarkably effective, but rather because there were no remedies quite as good. For smaller localized lesions surgery could be used, and recently the stilbamidines became available and proved themselves potent remedies for blastomycosis. Nevertheless, iodide continues in use largely because of its availability, low cost, ease of administration, and relative harmlessness. Furthermore, its position in the treatment of the deep mycoses often justifies itself, as in the cutaneous forms of sporotrichosis, where the drug is almost regularly effective and curative. The way iodide works against the deep mycoses remains unexplained. It is known to have little direct restraining power over Sporotrichum schenckii, as shown by survival of the organism in 10% solution.1 Yet iodide