Until I started doing research on the Golden Age Blue Beetle, I did NOT know he had a sidekick! This is the first appearance of Sparky, on both this page and the issue's cover. HOWEVER, he was not allowed to join Blue Beetle Dan Garret until the NEXT issue, which is a pretty ridiculous scheduling snafu!
The original Blue Beetle was a relatively big deal in the 40s, spawning comic strips and a radio serial, but he fell on hard luck when his original publisher, Fox, collapsed and sold him off to Charlton. Charlton couldn't keep him in print either, and created a new version instead, which was in turn picked up by DC some time later. Though I'd seen the original Blue Beetle in Rovin's Encyclopedia of Superheroes, I never saw him in a story before he showed up in a couple of issues of DC's Blue Beetle. It was pretty exciting.