Liarie Nicholosi, aged 11, Rochester, NY
What is a virus?
The newly invented microscope was a fascinating gadget. It showed the scientists of the day that plants were made of tiny cells. So were bones and body tissues. Then came an even bigger surprise. About 250 years ago, better microscopes revealed a whole world of tiny creatures, They were too small for human eyes to see. But the microscope forced the kingdom of microbes out of hiding.
Countless kinds of microbes and bacteria were discovered in the years that followed. The experts guessed, and soon proved, that many human sicknesses were caused by these midgets. One disease after another was traced to the criminals,. Though they measured on an average 25,000 to the inch, there were microbes that attacked people, plants and animals.
But in almost 300 years, no‑ one person could find what caused common cold, measles, mumps, polio and many other ills of people, plants and animals. In 1922, a Russian scientist was trying to cure a, sick tobacco leaf. He filtered the plant juices through a, fine porcelain. His microscope showed that no bacteria or microbes were present in the clear fluid. Yet this fluid could be made to infect healthy tobacco leaves. Obviously another criminal was present.
Other scientists developed the work. They named the invisible pests viruses from the Latin word for poisons. They called them filterable viruses because they are small enough to pass through fine pores in porcelain. One disease after another was tracked to these new found criminals. They cause our common colds and many diseases of plants and animals. They even cause sickness to the minute bacteria ‑ which shows how very small they are
The nature of the viruses 1s still under study. Under certain conditions, they act like simple chemicals. In other ways they act like living creatures. In size they compare to the molecules. The largest of them photographs to look like innocent balls of cotton.
The most important p1ace of information about the minute poisoners is this. They are parasites. They eat a.nd multiply only within the living cells of larger bodies. They refuse to feed on the chemical broths and serums that sustain the bacteria.
Some experts believe that the viruses were once more complex and have shrank to their present low level. By feeding on others they chose an easy way of life. But they jade themselves helpless and dependent. Others say the viruses may be the lowest and most simple form of life, and there are still think that viruses may be more than complex molecules of chemicals.
Even with the scanty knowledge we have, science has attacked many of the viruses. The vaccination scar on your arm was caused by a virus. This virus, which causes cow pox, was introduced into to your body. It’s job was to equip your body with weapons against the far more dangerous virus of smallpox.