Erratum.
In the letter by R. L. Brownell, Jr., and H. Omura (30 May, p. 976), an additional reference [M. Tomita and M. Nishimura, Jpn. J. Hyg. 28, 59 (1973), p. 44] should have been cited at the end of the first sentence of the last paragraph. Two sentences should have followed: "Tomita and Nishimura (1973) reported that the total mercury content of sperm whale meat ranged from 0.54 to 3.69 parts per million (ppm). However, mercury levels in meat from two species of baleen whales examined, sei and minke, were much lower, ranging from 0.04 to 0.12 and 0.15 ppm, respectively."