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Picture -5

-5. On the upper layer of keratin (1) a number of viruses are crowded together, as they often actually are on the skin. One of the larger ones is smallpox (2). A bacteriophage (3) of medium size as we saw in the previous drawing is shown here very distinctly from an electron- microscopic observation - just to give its size and shape, for it would not be likely to lie here by itself! Many molecules could be shown on this scale. Some starch molecules (4) are drawn. The inset shows the helical structure of the flagellum (5) as seen in the electron microscope. The flagellum clearly is composed of three strands wound into what looks like a cord. Magnification is here 100,000 times, about the maximum that can be reached with the electron microscope. The height of the salt crystal on this scale would be 50 meters.

1 cm. in picture = 10-5 cm. = 0.1 micron.
Scale = 100,000:1 = 105