John. Alexander, age 12, of Winston‑Salem :

 What is the smallest living thing?

Let 's begin with the word organ, which has several very different meanings. It can be a musical instrument, a newspaper or a body organ such as the skin: These: vastly different organs, and others, have however one thin; in common. They are instruments by which sore important activity is performed. The most important of all activities is the process of life.

Hence, any body which carries on this process is called an organism. The smallest of all living creatures is an organism. The smallest of all is called a micro‑organism.  _

These microorganisms can be studied only under a microscope. Even soy the powerful electron microscope can reveal only the shadows of the smallest of them. Experts do not all agree as to which are the smallest of all living things, 1ost of them say it is the bacterium. A few say that it could be the virus. However, if a bacterium were as big as a horse, a virus would be no bigger than a mouse. The virus is certainly smaller. But there is some doubt as‑to whet her it can be called a living thing. In some respects it acts like an organism. In others it‑acts like a non‑living, or inorganic mineral.

Viruses are small enough to wriggle through the finest filter. Some attack our bodies and cause diseases such as‑flu and smallpox. They seem to need food and are certainly able to multiply. These are functions of living organisms. On the other hand the viruses can form crystals like inorganic minerals such as salt and sugar.

These tiny thin s, so small that only their shadows can be seen by the electron microscope, seem to occupy a place between the world of living and the world, of non‑living things. The bacteria, however, are definitely organisms. Each bacterium can take in air and food and use them to carry on the functions of life. Each bacterium can multiply and hand on life.

Bacteria core in assorted sizes. If some were big as elephants, others would be as small as mace, There are countless varieties and whether we like it or not, they share our world with us. Some are friendly to us. They help digest our food, purify our water supplies and aid in the manufacture of cheese, vinegar, sauerkraut and other things. A few cause disease most of them are neutral to us, doing us neither good nor harm.

The average bacterium is a small blob with a tail or several tails which it uses to move around, It has no mouth and it cats by dissolving the chemicals it needs, ,1'Vhen foot' or moisture are scarce it waits indefinitely until things improve. When food is plentiful, it multiplies. And it multiplies by dividing in two. Each bacterium becomes its own children. So, it seems, the smallest of all living things has discovered the secret of immortality.