For a long time, the appendix was considered to be disposable. After all, millions of people get their own each year and continue to live a healthy life. But as Heather F Smith, professor of anatomy at the University of Midwest, said it to Ian Sample, researchers are increasingly understanding what this small worm in the form of worms can bring to the table in terms of health. Smith explains how the appendix is linked to both our development of the immune system and intestinal health, and why it thinks that an increasing interest in the microbiome can make it more important