"Great fleas have little fleas upon their backs to bite 'em, And little fleas have lesser fleas, and so ad infinitum, . . . "

A Budget of Paradoxes
Augustus de Morgan (1806-1871)

Microscopic organisms are unique and often unseen wonders that have as much (or more) diversity than macroscopic organisms. Since its invention, the microscope has served to focus our wonder and amazement at the microscopic world of the small, smaller, and smallest. Whether examining the root hairs on a plant, the spores of a fungus, or the organelles of a plant cell, the microscope allows your students to experience the intricacies of this hidden world that may seem unreal when simply viewed with diagrams or illustrations. Thus, the microscope is one of the most important tools in science laboratories, and it is essential in Plant Pathology where it is utilized in the identification of plant pathogens and their effects on plants.

Teaching students careful and appropriate procedures for using microscopes allows them to more easily utilize the instrument and helps protects the equipment from damage. An excellent source for teaching basic microscopy skills for both compound and dissecting microscopes can be found in Basic Microscopy -An Important Skill for Plant Pathologists by Melissa Riley. The exercise includes pictures of the microscopes with interactive labels as seen in Fig. 1 and Fig. 2.

Figure 1 Click on image to see labeled parts.

Figure 2 Click on image to see labeled parts.

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For additional information on microscopes and microscopy, try these websites:

• Authored by James A. Sullivan, Cells Alive (http://www.cellsalive.com/) provides an impressive selection of micrographs.
  
  
• At The Digital Learning Center for Microbe Ecology (http://commtechlab.msu.edu/sites/dlc-me/), you can visit the Microbe Zoo or meet the Microbe of the Month. Check out the Thanksgiving microbe. It's familiar to all plant pathologists.
  
  
• At http Marly Cain's Amazing Micronautic Adventures is a blend of fun, creative activities, and learning assisted by Merlin, the web-site guide, that will appeal to many students .
  
• The Brian J. Ford Science Website (http://www.sciences.demon.co.uk/whistmic.htm) provides The History of the Microscope including a picture of one of Leeuwenhoek's original microscopes.
  
  
• At http://www.life.uiuc.edu/plantbio/cell/, The Virtual Cell provides an intimate view of a plant cell and its organelles and other structures.

Views:This delicate tree-like structure is one example of the elegance of the microscopic world. It is the asexual reproductive structure of the downy mildew pathogen, Peronospora parasitica.