Wet mount- Motility of organism can be seen. However, it has to be differentiated from the Brownian movement.
Demonstration of flagella by staining: Silver impregnation cells or structures too thin to be visible under an ordinary microscope may be rendered visible if they are thickened by the impregnation of silver on their surface. These are used for the demonstration of spirochetes as well – Ryu’s Stain
Hanging Drop: The organism is to be looked at the periphery of the drop because organisms are generally aerobic.
Hanging drop method- Seal around by wax or paraffin
Capillary tube method- culture the organism in RCM and take it in a capillary and seal both ends of the tube and fix in a slide and observe under the microscope.
Organisms are motile due to flagella and motility tests use to detect the presence of ﬂagella by bacteria, allowing them to travel in and out of the microscopic ﬁeld or beyond their initial inoculation in agar. For the wet preparation, a drop of the organism in broth is suspended on a clean and grease-free glass slide, a coverslip is added, and the culture is observed microscopically for motility. Occasionally the organism is incubated in the broth prior to examination whereas, in the tube test, semisolid motility medium like SIM (Sulfide, Indole, Motility) or MIU (Motility, Indole, Urea) or MIO (Motility, Indole, Ornithine) is inoculated in a straight line down through the center of a tube. Motile organisms will migrate out from the line of inoculation, causing visible turbidity throughout the tube. Non-motile organisms will grow only along the line of inoculation.
Organisms tested-Campylobacter; Legionella; enterococci; Enterobacteriaceae; Listeria; Bacillus; other gram-positive rods; non-glucose-fermenting, gram-negative rods; and any other organism where motility is useful for identiﬁcation