The inside of the oral cavity is covered with a layer of squamous epithelial cells. These are relatively large, flat cells that are constantly being produced and rejected by the oral mucosa. It is quite easy to examine these cells microscopically.

It is not that often that I look at blood under the microscope. It usually happens when I get injured and have the opportunity to get a microscope. After an unfortunate shave, I act quickly so that I can prepare a slide from the blood before it dries up.

The reason for writing something about aphids was a Willow Tree in our garden that was infested with these very small insects. Aphids mainly reside on young leaves and stems. With the naked eye there is not much more to see than small, slowly moving oval shapes that are a few mm in size. All the more reason to have a look at them under magnification.