CREATE TABLE table_39979 ("Species" TEXT, "Indole" TEXT, "Methyl Red" TEXT, "Voges-Proskauer" TEXT, "Citrate" TEXT)

What is the methyl red reading for the species that tests positive for indole?
SELECT "Methyl Red" FROM table_39979 WHERE "Indole" = 'positive'
SELECT "Methyl Red" FROM "table_39979" WHERE "Indole" = 'positive'