Bacteria of the species /Bacillus subtilis/ were inoculated at the center of a dish with gelose containing nutrients. The bacteria start mass-migrating outwards about twelve hours after inoculation, forming dendrites which reach the border of the dish (diameter 90mm) within a few hours. Two days after inoculation the number of bacteria has increased so much that they diffuse light significantly and appear white. This picture was taken against a lightsource to make the dendrites (white branched structures) clearly stand out.