Tarzan's son (from the Weissmuller era) and 'Bomba' in the Jungle Boy Monogram Pictures' series is no more: http://www.latimes.com/news/obituaries/la-me-johnny-sheffield-20101019,0,6703159.story
Sheffield, who had appeared in "On Borrowed Time" on Broadway in 1938, recalled in a 1997 Times interview that there were two parts in testing for the role of Boy.
"The first was just talking to Weissmuller, and that was no problem," he said. The second part was a swimming test, which for young Sheffield presented something of a problem: He couldn't swim.
The swimming test with Weissmuller, the winner of five Olympic gold medals in swimming, was held at the Hollywood Athletic Club.
"He jumped into the deep end of the swimming pool," Sheffield told The Times in 1997. "He knew I couldn't swim. He said, 'Jump in.' I jumped in the deep end and he took my arm and set me on his knee. He said, 'You're doing fine. Hold your breath, we're going under.'
"We [later] did a lot of those scenes like that in the movies, where I was holding on to him underwater and swimming. We got out of the pool, toweled off and he said, 'This kid can swim fine.' "
Weissmuller was always "kind and tender toward me," Sheffield told the Associated Press in 1984, shortly after the actor he called Big John died at age 79.
"He was like a father to me," Sheffield said. "He was always looking out for me. We worked with a lot of live animals, and a lot of times, when they got tired, the animals would get feisty.
"There was this one big chimp who got pretty mad one day and was about to bite me while we were on the set. But Big John stuck his leg between me and the chimp, and he was the one who was bitten."