A review of the literature shows that the subcutaneous implantation of stilboestrol increases rate of gain in weight and efficiency of food conversion in lambs (Andrews, Beeson & Harper, 1949; Jordan, 1950; Perry, Andrews & Beeson, 1951; O’Mary, Pope, Wilson, Bray & Casida, 1952; Means, Andrews & Beeson, 1953) and in cattle (Clegg 8t Cole, 1954). The oral administration to fattening steers of s...