Certainly one of Hastings' students, Ken Nealson, theorized that they were secreting a chemical that accumulates in their environment until the group reaches some threshold density. He christened this unknown molecule an "autoinducer." Nealson's hunch turned out for being accurate, and the chemical system by which V. fischeri this work. https://businessinsider54321.mybjjblog.com/fascination-about-spine-pr-41339185