Imagine that youve prepared a hanging drop slide but were ca

Imagine that you’ve prepared a hanging drop slide but were called out of the room for an hour before being able to look at it. When you return, examination of the slide showed no motility. Would you be satisfied with this result? Why or why not?

Solution

Hanging drop preparation is a special type of wet mount (in which a drop of medium containing the organisms is placed on a microscope slide), often is used in dark illumination to observe the motility of bacteria.

In this method a drop of culture is placed on a coverslip that is encircled with petroleum jelly (or any other sticky material). The coverslip and drop are then inverted over the well of a depression slide. The drop hangs from the coverslip, and the petroleum jelly forms a seal that prevents evaporation. This preparation gives good views of microbial motility and remains for a long time.

No, I would not be satisfied with the above result because there is no chance of dryness of the sample drop due to presence of petrolium jelly.