Bacterial Vortex Simulation (video) Brown University Loading video... Caption When confined in a water droplet, B. subtilis bacteria collectively and spontaneously form a swirling vortex, with some bacteria moving in one direction and others moving the opposite way. Researchers from Brown University and the University of Cambridge have shown that fluid flow generated at the outer edge of the droplet accounts for the two-directional motion. Credit Brown University / University of Cambridge Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.