Others have pointed out the similarity of eden ahbez' melodic theme to the 2nd movement of the Dvořák Piano Quintet In A Op.81. Ahbez came to Los Angeles as George Aberle and started playing piano in the Eutropheon health-food store and spiritual centre, becoming one of its Nature Boys. Assuming he was a classically-trained pianist he would have been familiar with the Piano Quintet and its delightful and slightly sad themes.
Dvorak named this movement "Dumka" to emphasise that it was in the form of a traditional Slavonic folk ballad. "Nature Boy" uses a direct quotation from the beginning of the movement, echoed by the phrase
"There was a boy, A very strange enchanted boy"
They say he wandered off into his own melodic inventions for the subsequent development, but the mood of the song maintains that of the folk ballad
It must be that ahbez was not consciously aware of the influence of the Dvorak because he came to a financial settlement with another composer who claimed the copyright for his own composition. In 1935 emigré musician Herman Yablokoff had written Shvayg mayn Harts (Hush My Heart) for a Yiddish theatre production in NYC. This in turn was based on a Klesmer tune, Papirosn (meaning Cigarettes), so it is conceivable that Kodaly himself knew the tune.
Here is an example of the Dvořák quintet
For an example of a recording of the Quintet on 45worlds see LXT 6043
'Nature Boy' brought Nat King Cole to the attention of the general public. It was written by what we would later call a hippie, namely eden ahbez (capital letters on the label) but later rectified. It reached No.1 on the US Best Sellers for seven weeks in April/May 1948.