Source, in full
In an essay by Ralph Waldo Emerson, "Solitude and Society" in The Atlantic Monthly, Vol. 1, (December 1857), p. 228, this follows a statement clearly attributed to Bacon, which might be a paraphrase. Without explicit citation, this is added to the parapgraph with quote marks but seems to be a paraphrase of lines by William Shakespeare, from King Henry IV, Part II, Act V, scene 1: "It is certain that either wife bearing or ignorant carriage is caught, as men take diseases, one of another: therefore let men take heed of their company."