Index >> Microscopy Methods in Microbiology >> Observation Of Bacteria Protozoa And Algae

Observation of bacteria, protozoa and algae
For the best demonstration of this preparation to students, it is advisable to use hay-infusion broth as a sample. Antony Van Leeuwenhoek used the same material and described the microbial world for the first time. This allows one to observe bacteria, algae and protozoa.

Hay infusion broth can be easily prepared by adding small amount of hay in water and keeping it in an open container till turbidity in the water develops. The following sequence of steps fro the wet mount preparation is recommended to ensure satisfactory result.
(i) Using tooth-pick or needle prepare a square of petroleum jelly of size smaller than a cover glass on a clean slide.

(iv) Observe the preparation immediately under the high power objective.
The movement of amoeba and other protozoa has been found to be ceased when they are kept at room temperature, lower than the body temperature. To examine movement of such organisms warm stage is very useful. Warm stage is a device to warm the slide, usually electrically or by circulating warm water, without disturbing the viewing area of the preparation.