He's been with More Fun since issue #7, so about time I use a panel of what is DC Comics' longest living character. He appeared in that series until issue 32 (June 1938), then dropped off the map completely until Who's Who #6 (1985) reminded Roy Thomas to use him in All-Star Squadron. Since then, he's appeared sporadically in Superman comics (the Siegel & Shuster connection), Vertigo stuff (including his own special), and mysticism-oriented titles and story lines. He's even had a smattering of appearances in the New52!
All of which makes you think he had a proper Golden Age strip boldly credited to Siegel and Shuster. The truth is a bit different. Like all strips in More Fun at this very early point, the Doc has only two pages to work with, and they're in the black and white section of the magazine. There are multi-part stories, but somehow they managed to tell this one as a one-off, with our hero basically explaining the plot to the audience in the last panel, above. That's one hell of a shortcut. It's also interesting that the story is credited to "Leger and Reuths", pen names for the duo that would eventually give us Superman. Interesting and strange, given that they produced other strips for these mags under their real names, and Shuster's art at least, is pretty distinctive.