Page:Amazing Stories Volume 15 Number 10.djvu/136

136 the tidbit and pursues it if an effort is made to take the "food" away.

UT there is a still more complex and striking similarity between the living and the lifeless organisms. An amoeba frequently eats a string of algae much longer than itself. This it absorbs in a striking way by drawing in a loop of the string and gradually coiling it into a long spiral within its body. Weirdly, a chloroform droplet, offered a string of shellac, attacks and eats it in exactly the same manner.

Still the imitations of life are not complete. The Difflugia, a relative of the amoeba, covers itself with a fragile and lovely shell made of sand grains, diatom shells and other bits cemented together so cleverly that not a joint can be located under the microscope. There, we say, is a power exclusively reserved for a living creature. But is it?

If our oil drop is rubbed up with a fine dust of ground glass and injected into water, it immediately builds itself a single-layer shell of delicacy and texture that is almost indistinguishable from that of a living Difflugia.

Still more startling were the results gained by Drs. Crile and Telkes at the Cleveland Clinic. They used droplets of oil extracted from the brains of freshly-killed rabbits and found not only all the characteristics previously mentioned for ordinary oils but the presence of a nucleus, as well. Furthermore, they found evidences of respiration, pointing to true chemical reaction within their artificial "animal". Further experiments revealed that these obviously non-living drops could be "killed" by poison, suffocation or starvation in exactly the same way that the amoeba, the rabbit, or even man. are so killed.

But, sensational as this science of plasmogeny, as one researcher calls it, is it represents but a single step out of many science has taken in its efforts to understand and recreate life. There are others more incredible.

AKE our nerves, for example. We know that nerve impulses are electrical in nature, can be measured by electrical instruments and timed as to speed. A nerve can be stimulated by the application of electricity, an irritating chemical, or by simply striking or tearing or stretching.

Dr. R. S. Lillie of the University of Chicago treated a length of iron wire with acids and got almost a perfect artificial nervous system. An electrical negative charge traversed the wire at a speed slow enough to be followed by the human eye—a speed that almost exactly corresponds with the speed of certain nerve impulses, whereas an ordinary electric current flowing through a conductor travels at the speed of light.

Furthermore, the application of acids or simply tapping, bending or stretching one end of the wire sent an identically similar electric impulse traveling over it.

After a nerve in our bodies carries an impulse, it 'goes dead" for a brief period, becoming a non-conductor. This is to prevent a "kickback" of the impulse. Strangely, the wire "nerve" created by Dr. Lilly showed the same "refractory period" which resulted in making all impulses maintain the same direction as they do over our own nervous system.

In the human body, certain nerve impulses are rhythmic and automatic, like those controlling the beating of the heart, for example. Dr. Lillie's wire held a charge at one end and sent it out through the remainder in regular rhythmic impulses. Again one of the characteristics of life was imitated artificially.

OR years, scientists maintained that the ability to form crystals was wholly and entirely a characteristic of non-living matter. No microscope was strong enough to show even traces of crystal formation in organic matter. Nevertheless, the habit of crystals arranging themselves into forms that strikingly imitated living organisms made many scientists wonder if there were not a hidden connection somewhere.

If we allow a saturated solution of salt or sugar and water to evaporate to a point where crystals begin to form, we see the usual irregular planes and angles of large crystals. Surely, nothing like a living form is visible in their geometric mass.

But add a bit of gelatin or starch or any other slimy matter to that solution and notice the difference. Immediately the large crystals break up into masses of smaller ones that regroup them- selves into an almost perfect resemblance to a plant leaf.

Crystals imitate life in many other striking ways. For example, crystallized starch takes the form of living cells, many of them even possessing cell walls and a nucleus. Spiral formations, so common in simpler life forms, is beautifully imitated by the spiral organization of paraffin crystals.

Anyone can make beautiful artificial "plants" that actually grow and act like living cora. A crystal of potassium ferrocyanide, placed in a one per cent solution of copper sulfate will, within a few minutes, start to grow. Shoots spring up. These spread out into branches and leaves until a beautiful plant is formed—simply by the osmotic growth of the crystals. A pill, moulded of cane sugar and copper sulfate, dropped into a solution of yellow prussiate will produce an even more lifelike and elaborate shrub. The most gorgeous forms of all are produced by dropping various metal salts into sodium silicate or water glass. Many-colored plants are formed, complete even to branches, leaves, blossoms and buds.

With lime salts in a soda solution Stephane Leduc grew artificial mushrooms so realistic that even botanists mistook them for real mushrooms. Even the internal fibrous structure of the stems was similar to that which nature builds into her product. With similar methods, Leduc also grew strikingly realistic artificial nerve cells, complete even to nerve fibers sprouting from a ganglion.