[math-fun] Dr. Matrix reference

In Martin Gardner's book "The Incredible Dr. Matrix", in chapter 13, page 120-121 in my edition, "Dr. Matrix" says "You once quoted me as saying that the decimal expansion of pi, properly interpreted, contains the entire history of the human race." Since he says that he was previously quoted, I wanted to find the original passage. I skimmed all of the previous chapters twice, but I couldn't find it. Can anyone tell me where the original "quotation" is? Thanks.