Considering the ease with which disease germs may enter the body, it may seem strange that a person is not constantly ill with some disease.We know, however, that not every person exposed to infection contracts the disease.There are a number of reasons for this.

What is the effect of the unbroken skin?What happens to large amounts of dirt and dust of the air which is breathed in through the nose ?What is the appearance of the mucus which is blown out of the nose after you have been working in a very dusty place ?Not only does the mucus catch some of the germs that are breathed in and permit their removal but it has been found that it possesses some power to kill the germs.Suggest one reason for breathing through the nose rather than through the mouth.

Even though these outer defenses of the body are passed, the germs are not permitted to develop unchecked.The body offers a certain resistance to the attacks, partially by means of the white blood corpuscles which engulf the bacteria, and partially by the resistant power of the blood and living parts of the body, a power which is not so easily understood.

This power of resistance is affected by a number of things.The fact that certain diseases occur only in childhood indicates that age is one of the factors concerned.A poor diet, excessive fatigue, extremes of heat and cold, lack of sleep, lack of fresh air, and weakness from other diseases are conditions which lessen the power of the body to resist disease.In general, any condition which increases the health of the body increases its power to resist disease.Because of this fact, ‘outdoor life, deep breathing, moderate exercise taken regularly, a proper amount of sleep, and good food are not only the preventives of disease but in some cases constitute a cure by giving the body a chance to fight off the enemy that has already gained a foothold.

You could study the mechanism of host defense such as our immune system and our systems that prevent infection such as the skin layers and mucous membranes in our nostrils in our nose.