Monthly Archives: April 2014
245.WHY DO WE BLINK OUR EYES?
When we drive a motor-vehicle in bad weather, it is very important to have the windscreen wiper working efficiently. Yet the best windscreen wiper ever made for any car can’t compare with the “windscreen wiper” nature has given us for our eyes!
The lids of our eyes, which move up and down when we blink, are our built-in windscreen wipers. The lids are made up of folds of skin, and they can be raised and lowered by certain muscles. But they move so rapidly that they don’t disturb our vision in any way.
244.WHAT IS TYPHOID FEVER?
As man learns how to keep himself more clean and sanitary practices spread through the world, some of our worst diseases are gradually eliminated. One of these is typhoid fever. Just 60 years ago, thousands upon thousands of people were dying from it every year. Now deaths from typhoid average only a fraction of what they were, and are now confined mainly to the more backward regions.
Typhoid fever is caused by a bacillus called Salmonella typhosa. It lives in the products of excretion. After it leaves the body, the bacilli can continue to exist, but they do not multiply.
243.WHAT IS TB(TUBERCULOSIS)?
TB, or TUBERCULOSIS, is a disease caused by infection by a germ known as the “tubercle bacillus.” It is, unfortunately, a common infection in all parts of the world, and is most common where people live in crowded, unsanitary conditions and have poor nutrition.
Luckily, man has strong resistance to the infection. About 90 per cent of the people who live in cities develop at least a small spot of infection at some time or other, but most do not even know they have it. Less than 10 per cent of people infected with TB die of it.
