Thus the liver owes its great size partly to the large amount of blood-purifying, filtering, and poison-destroying work which it has to do, and partly to its acting as a storehouse of starch and fat, which the body can readily draw upon as it needs them.
[Illustration: OUTLINE DIAGRAM SHOWING GENERAL PLAN AND POSITION OF BODY-MACHINERY] As all poisons formed in, or entering, the body are brought to the liver for destruction, it is in an extremely exposed position, and very liable to break down under the attack of these poisons, whether of infectious diseases, or chloroform, or alcohol, or those formed by putrefaction in the stomach and intestines.

This is why those who have lived long in the tropics and suffered from malaria, dysentery, and other infectious diseases, and those who drink too much alcohol, or have chronic indigestion, or dyspepsia, are likely to have swollen and inflamed livers.
The Gall Bladder.

The liver has on its under side a little pear-shaped pouch called the _gall bladder_, in which the bile is stored before it is poured into the bowel.

If this becomes inflamed by disease germs, or their poisons, in the blood, little hard masses will form inside it, usually about the size of a grain of corn, known as _gall stones_.

So long as they stay in the gall bladder, they give little trouble, but if they start to pass out through the narrow bile duct into the intestine, they cause severe attacks of pain, known as "gall-stone colic," and, by blocking up the duct, may dam up the flow of the bile, force it back into the blood again, and stain all our tissues, including our skin and our eyes, yellow; and then we say we are _jaundiced_.