Therein lies another story.
Irving Mills is a central character in my tale of St. James Infirmary. So it is good to actually hear his voice.
Pettis, though, was Caucasian, as were the members of his bands; an innovative saxophonist, he recorded occasionally with Mills' "Hotsy Totsy Gang" alongside such youngsters as Tommy Dorsey, Benny Goodman, Jack Teagarden, Gene Krupa ... all soon to become among the biggest names in jazz/pop music. Mills had an uncanny way of recognizing talent.
You can read more about Jack Pettis here.
It is likely that Mills was managing Pettis when this record was made. "Baby" was written by two of Mills' stable of songwriters, early in their careers, Dorothy Fields and Jimmy McHugh. Both were eventually inducted into the songwriters hall of fame.
Mills' vocal comes in at about 58 seconds.