In the production number ("I Found a Peach on the Beach") at the end of the nightclub act, Lucy and Ethel are singing a line with the words, "We'll make a peach of a pair". On the last repeat of this line, the arrangement calls for them to leave out the last word ("pair'), as the music changes for a brief dance step. Ethel (Vivian Vance) remembers only at the last minute, and begins to sing the word anyway.
Here we meet Barney Kurtz, Fred's old Vaudeville partner, and Lucy and Ethel recall the name of the act as "Laugh 'til it Hurts With Mertz and Kurtz". In The Ballet (1952), Fred's old partner (unseen) is called Ted Kurtz, and he refers to the act as "Mertz and Kurtz, the Laugh Twins". (In the sketch Fred re-creates, he seems to capitalize on the similarity of the names, especially the first names - Fred/Ted, Freddie/Teddie, &c.)