Page:Amazing Stories Volume 15 Number 10.djvu/135



N past revelations of Scientific Mysteries we have sought elusive unsolved riddles in the most obscure places—on the moon, in pre-historic ruins on earth, among queer races of peoples, in all sorts of out-of-the-way places. In so doing, we have avoided at once the commonest and the most bewildering of all the mysteries that face science. It is a mystery that manifests itself in us and around us, wherever we are. In fact, we ourselves are the greatest mystery of the universe, along with every other living thing both great and small.

Exactly what is life? How can Life be defined? What is the difference between a living and a non-living, or dead, object?

Almost everyone thinks he can answer that last question—almost everyone, that is, except scientists who have studied the subject for generations. As a matter of fact, there is almost no known characteristic of a living form that is not duplicated by some non-living form. Today, scientists are creating artificial life forms in their laboratories that are so similar to living creatures that to the outsider it begins to look as though there is actually no dividing line at all between living and lifeless matter. Science says there is—but it's having a harder and harder time to prove it in a satisfactory manner.

What are the common characteristics of living matter? Well, living matter usually exhibits the ability to grow and reproduce and move about in its environment, to respond to external stimuli and to take nourishment. Many schools today are teaching their pupils that if an organism or particle of matter can do those things, then it is alive. What a rude shock those teachers would get if they could visit one of the modern laboratories where research into the origin and meaning of life is being conducted.

AKE the supposed life=characteristic of growth. Living organisms grow, and with growth they also reproduce. the simplest single-celled organism grows for a time and them becomes two cells, either by cell division or by budding or similar means.

Almost everyone is familiar with the common single-celled microscopic animal, the amoeba. About a fourth of a millimeter in diameter, the amoeba is an irregularly-shaped organism, colorless and invisible to the naked eye. The amoeba moves by pushing out shapeless "feet" or pseudopods at odd points while at the same time, it uses that movement to stream the medium in which it lives through its own body. As this liquid streams through, the amoeba extracts food it desires and ejects any inedible particles like sand. When food is plentiful,. the amoeba grows noticeably larger and then divides into two distinct amoebae that go their respective ways.

The amoeba represent simple life in action. But—so do a number of non-living substances.

a minute drop of oil place in water to which ahs been added some activating chemical will apparently become a living amoeba. Dr. Jennings, professor of Zoology at Johns Hopkins University, uses droplets of olive oil floating in glycerine which contains some alcohol for his sensational experiments.

With nothing more complicated that his oil drops, anyone can perform this same experiment. Th oil drop is round at first. Then, exactly like the amoeba, it begins to move about by putting out pseudopodia. If it grows large enough, it divides exactly as the amoeba did, and becomes two separate "organisms." Streaming takes place internally. A heavy oil like chloroform will even go so far toward imitating life as to actually digest bits of shellac. If the shellac is coated over sand grains or glass particles, the artificial creature "eats" the shellac and excretes the particles. if an "inedible" substance like a bit of glass or wood is offered to this artificial organism, it immediately retreats. If the particle is force inside the drop, it is immediately ejected with some force.

But if any of a number of other particles—shellac, paraffin, styrax, Canada Balsam, etc.,—are held near, the artificial animal actually reaches out for