Lesson 3 - Page 1


Leeuwenhoek's complex slide preparation.

Preparation of the 1800's still being used today (permanent mounts)

Storing slides is important to
keep them safe


There are many ways to look at microorganisms under a microscope.     Some hobbyists just like to look at different critters.  Researchers may use the microscope to learn about the specific life cycle of organisms, whiles others will look at their habitat.  Government agencies may use the microscope to determine if a body of water is polluted or clean by identifying key species.  Teachers use the microscope to allow students to see a world they would otherwise not see.  Depending on what you are using the microscope for will depend on your slide preparation.  Some techniques are that were used in the early history of microscopy are still being used, whiles others like Antonie van Leeuwenhoek’s preparations are not used. 

Some techniques require that the organisms become immotile to observe its features, while others allow you to see the organism alive and healthy.  We will investigate 4 types of slide preparation including a permanent slide, a dry mount, a wet mount, and a live mount.

A permanent mount uses an embedding liquid so the specimen can be observed for a very long time (hundreds of years).  There are commercial slides that you can purchase and most of these are permanent.  Common medium used are natural resins like Canada balsam or synthetic resins like Permount.  The type of medium helps to control the effects of refraction from the glass slide to the medium.  Depending on the specimen is dependant of the type of medium that you use.  Many permanent slides use different staining techniques to help see features clearer. 

Permanent mount of tissue with stain

Labeling permanent mounts is important


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