Sulfide indole motility (SIM) medium tubes were inoculated with a nonmotile Staphylococcus (left) and a motile member of the family Enterobacteriaceae (right) by stabbing with an inoculating needle.  Both tubes were incubated at 37°C for 48 hours. Motility is evidenced via the diffuse growth of the Enterobacteriaceae throughout the medium as contrasted with Staphylococcus growth restricted to the stab line. (Clarissa L. Kaup and J. L. Henriksen, Bellevue University, Bellevue, NE)