How did these songs reach the public? Some were from American operettas. This genre had already produced its first lasting work, Julius Eichberg's The Doctor of Alcantara, in 1862. It had its first long string of successes in the 1870s with David Braham's Mulligan Guard shows.
The burlesque theater at this time was a subgenre of operetta. Songs from burlesque seldom bore the word "burlesque" on their title-pages. Names of popular burlesque performers such as Emma Thompson or Eliza Weathersby help identify songs from burlesque, as do the illustrations on some covers.
The source most often identified specifically on sheet music is the minstrel troupe. By the 1870s these troupes performed a wide variety of music besides the "plantation sketches" of the early minstrel tradition. A search on the subject "minstrel" in this collection will bring up songs identified with minstrel troupes, as well as a few songs identified with particular genres specific to minstrel shows: "end songs" and "walkarounds." By this period there were African-American minstrel troupes, often known as "Georgia Minstrels," performing repertoire similar to that of blackface minstrel companies.
Songs introduced on the variety stage, which was in the process of transforming itself into vaudeville, are often identified by performer but are seldom identified as variety songs. Two notable performers in this medium were Tony Pastor and Gus Williams. The opening of Tony Pastor's Music Hall in 1881 is often given as a date for the transition to vaudeville.
Songs were also introduced in plays. The boundaries between play, operetta, and series of variety sketches were flexible in the 1870s and 1880s--many of the operettas for which David Braham supplied the music are identified on their sheet music as "plays" by librettist Edward Harrigan--and such productions as The Tourists in a Pullman Car seemed to partake of all possible theatrical forms. This collection has perhaps tended to take the description "play" on sheet music a bit too seriously; several such works may well be operettas or variety turns. But the play with music is a genre of the period: the most-often-performed play with music of the era, Uncle Tom's Cabin, might have almost more singing than speaking (what was sung varied from production to production), but people came to see Eliza escape across the ice. A few publications of melodramatic music for plays suggest what music might have accompanied her escape.