This old and well-worn gag consists of the performer asking someone, “Do you know what is written on this card?” and, after the person says, “No,” he shows the word “No” written on the card.
This gag appears in a two-page manuscript, "The Supreme One-Man Mindreading Act". Unfortunately, this document (a duplicated typescript, carbon or mimeograph, found in one of Sid Lorraine's files) bears neither a date nor an author; and the title was used for several different manuscripts advertised between 1920 and 1935. That said, it is likely the one touted by a couple of dealers in magazines from 1930. See The Linking Ring, Vol. 10 No. 2, Apr. 1930, p. 258; and Vol. 11 No. 2, Apr. 1931, p. 137 of the same journal.
What is interesting about the routine described in this manuscript is that the gag is not just a throw-away. Rather, it is part of a larger method, used to enable a one-ahead construction. The write-up gives no suggestion that this was an existing gag. While that is not proof that the idea was original to the anonymous author, it at the very least suggests that the gag was little known at the time. Had the gag been an established one, the author would likely have touted the fact that he was applying it to greater purpose.
Another description of the gag, which is believed to have followed shortly after the release of “The Supreme One-Man Mindreading Act”, appeared in an article by Barkann Rosinoff, “A Spirit Slate Routine”, published in The Sphinx, Vol. 31 No. 7, Sep. 1932, p. 254. Rosinoff also uses the “no gag” for a dual purpose in his routine.
Another early appearance of the “no gag” occurs in George Kaplan's “Surrealism” in The Sphinx, Vol. 39 No. 10, Dec. 1940, p. 243.
The best-known published source for the “no gag” is Tony Corinda's 13 Steps to Mentalism, 1958, p. 103. (This history was assembled by Max Maven, with an additional citation supplied by Bill Mullins.)