Here are two recordings of Fanny Brice herself singing this song. I listened closely to the "Lux"/"lox" lines in each.

The first appears to be from a Victor recording. It sounds like she rhymes "shucks" with "lox". The second line is definitely "mit lox". The first line is less clear, but sounds more like "Taste it but shucks" than like "Tastes just like chalk" to me. In this verse, she has put on a bit more of a Yiddish accent than in the first two verses, so the near-rhyme is closer.

The second is an excerpt from the movie 'Be Yourself!' (a 1930 movie starring Fanny Brice and Robert Armstrong). She sings, "Taste it". He does and replies, "Aw shucks! Who the heck likes oatmeal, Sprinkled with Lux?" fairly clearly.

In addition, each has several minor changes from the lyric above; different from each other as well.

"The folk process" in action, I guess. Listen to them and make your own choice.

BB,
NightWing