Your article refers to “the current theory that high intelligence arises from the coating of brain cells with especially large amounts of the fatty substance called myelin.” As a person with multiple sclerosis, anything about myelin interests me greatly, yet I have never heard of this.

Marion Leeds Carroll
Arlington, Mass.

For more, see Daniele Posthuma’s chapter in Behavioral Genetics in the Postgenomic Era ( 2003, Robert Plonim, et al., eds., American Psychological Assoc .).—B. Bower