ffete matter.

_Alcohol not only hinders the blood in its work of tissue nutrition; it
also prevents the full oxidation of the blood in the lungs._

"In order that a steam engine may work and keep warm it is not
merely necessary that it have plenty of coal, but it must also
have a draft of air through its furnace. Chemistry teaches us
that the burning in this case consists in the combination of a
gas called oxygen, taken from the air, with other things in the
coals; when this combination takes place a great deal of heat
is given off. The same thing is true of our bodies; in order
that food matters may be burnt in them and enable us to work and
keep warm, they must be supplied with oxygen; this they get from
the air by breathing. We all know that if his supply of air be
cut off a man will die in a few minutes. His food is no use to
him unless he gets oxygen from the air to combine with it; while
he usually has stored up in his body an excess of food matters
which will keep him alive for some time if he gets a supply of
oxygen, he has not stored up in him any reserve, or, if any, but
a very small one, of oxygen, and so he dies very rapidly if his
breathing be prevented. In ordinary language we do not call
oxygen a food, but restrict that name to the solids and liquids
which we swallow; but inasmuch as it is a material which we must
take from the external universe into our bodies in order to keep
us alive, oxygen is really a food as much as any of the other
substances which we take into our bodies from outside, in order
to keep them alive and at work. _Suffocation_, as death from
deficient air supply is named, is really death from
oxygen-starvation."--Martin's _Human Body_.

Much of the food taken into the body is burned to supply energy and
heat. This burning is called oxidation. When food is burned, or
oxidized, either in the body, or out of it, three things are produced,
carbon dioxide (_carbonic acid gas_), water and ashes. These are waste
matters, and must be expelled from the body, or they will clog up the
various organs, as the ashes and smoke of an engine would soon put its
fire out if they were allowed to accumulate in the furnace. It is the
duty of the lungs to pass the carbon dioxide out to the air. With every
breath exhaled, this poison gas, generated in the body through the
oxidation of food, passes from the