Q. How many bacteria are on our skin?
A. There are 5 million bacteria on every square centimetre of human skin.
Q. What are 'worms'? How do we contract them? How do they make us thinner?
A. 'Worms' are more commonly tapeworms or roundworms. Animals pick them up from contaminated soil of the faeces of other animals. We can also contract them if we don't wash our hands thoroughly with soap after patting animals, and then go to eat. They make us thinner because they find their way to our digestive tract and eat part of our food.
Q. Why are some oral medicines (tablets and capsules) sugar-coated or gelatine-coated?
A. The type of coating determines where the coating will be broken down in the digestive tract, and once it is digested then the inside medication can be used by the body. The type of coating acts as a time delay. Sugar begins to be digested in the mouth and later in the small intestine. Gelatine is a protein which is digested in both the stomach and the small intestine.
Q. Why do we put food in the refrigerator?
A. Lower temperatures slow down the growth of bacteria and fungi that would otherwise decay our food or give us food-poisoning.
Q. Are all bacteria harmful?
A. No. Only some bacteria cause diseases. Many are useful. For example, there are decomposing bacteria that break down dead plant and animal matter and faeces and urine into nutrients that plants can use. Also, some bacteria in our gut make vitamins B and K for us.
Q. Did Egyptians do surgery?
A. The Egyptians were probably the first people to use sophisticated medical methods. They used trepanning, that is, cutting a hole in people's skulls to release the fluid pressure after a head injury. The method is still used today.
They also saved victims of snake and scorpion bites by sucking out the poison and tightly strapping the wound.
Q. What was used in surgery before anaesthetics were invented?
A. Before 1846, there were no anaesthetics used and the patient was still conscious during surgery. Early self-experimentation of nitrous oxide (laughing gas), ether (which is flammable) or chloroform by anaesthetists often resulted in anaesthetists becoming crazy or setting fire to their surgeries.
Q. Is it healthy for people to spit?
A. Rarely. A human swallows half a bucket of saliva each day. The human stomach contains hydrochloric acid that rapidly kills most bacteria that we swallow. The fluids that are expectorated (spat) will simply evaporate for other people to inhale. So, in effect, unless your doctor needs a sputum (spit) sample, there is no need to spit.
Q. Why do people who intend working in remote areas such as Antarctica have appendectomies and tonsillectomies before going there?
A. There are no facilities as yet to carry out major surgical procedures in this remote place. Ships also are unable to reach the Antarctic during winter.
Q. Why don't we get sick from handling money that hundreds of other people have also touched?
A. Bacteria grow very well in moist, warm conditions particularly where they have food such as protein and some sugars. Money has none of these and is not the most suitable environment for bacteria to flourish.
Q. What type of school lunches in summer will give the least possibility of food poisoning?
A. Since bacteria grow well if proteins and some sugars are present, foods that will not allow a lot of bacterial growth on hot days are fruit and vegetables. Have salad sandwiches without the meat!
Q. Why do paper cuts hurt more than a razor cut?
A. Paper cuts hurt more than a cut with a razor because paper not only cuts but it also tears the skin apart roughly, causing more damage.