The Boswell Sisters, also influenced by a brother, were harmonic singers in the early part of the century. One of their songs actually named, "rock and roll", in reference to being on a ship at sea. Or, on the Mississippi. They became very popular, and were even in movies, including, The Big Broadcast of 1932, with Bing Crosby. Well, Bing went on to spent a virtual lifetime hooking up in songs and movies with the Andrew Sisters, from Minnesota, who had been completely inspired by the Boswell Sisters. I also want to note a personal observation. It seems to me that the Boswell Sisters were influenced by the mid-to-late 1800's "Dance Hall" style of songs, written in England, and carried over to the U.S.A. THAT is another interesting subject to read about.
Well, then we get to the Andrews Sisters. I won't get into a discussion of this mega-popular group, who played with every great big band in the 1940's, and did for WW2 what the Boswell Sisters did for WW1. But I do want to mention one of their now-lesser-known songs from 1950. It was a song taken form the 1930's, and was a number one hit for the Andrew Sisters. It was their biggest hit before their disbanding in 1955.
It is, "I Wanna Be Loved." Listen to it - it is amazingly sensual, for the 1950's. I see it as being a bridge from the lost 1920-30's to the rising 1950-60's. It's one of those amazing pearls, like those from Monroe, and early rockers. It is kind of interesting, though, that it also marked the end of an entire era, and the beginning of the rock and roll, beatnik, hippie era. I guess it had to be, when, in fact, the new era, was not so different from the 1920-30's, with all it's lasciviousness, and then it's rebellion against the Big MAN.
History does not repeat. It rhymes. Thus, it is required that there always be a complete break from the past, so the future can march on. Only in retrospect do we see the rhymes in what those children believed were revolutions.
It might not seem possible that the Boswell Sisters could have influenced R&R, since they happened so long ago. But the roots of R&R go way back before the phonograph. I think these sisters pulled up a lot of Louisiana sounds which were to to one day become R&R. As usual, it took whites to bring these sounds to the greater population's attention. I don't think it would be too difficult to trace a line between Boswell's and true Rock and Roller's of the 1950's. I think it is 100% probable that they directly influenced R&R, but are not yet seen as doing so, since they are female.