These pictures show real snow crystals that fell to earth in Northern Ontario, Alaska, Vermont, the Michigan Upper Peninsula, and the Sierra Nevada mountains of California. They were captured by Kenneth G. Libbrecht using a specially designed snowflake photomicroscope.
Axones nerviosos - A cross section of a bundle of nerve fibers. Axons (orange) are wrapped in myelin (purple); an extension of the membrane of glial cells. Myelin has high lipid content, and acts to insulate the axons, causing them to transmit nerve impulses much faster.