[Numbers count down.]
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[Narrator:] ...upon which they place drops and inhale the smoke through tubes inserted in their nostrils.
This was the first acquaintance of white men with tobacco.
The fragrant leaves of the Indians quickly spread around the world.
Today the labor and skill of thousands of families goes into the growing and processing of tobacco.
Tobacco plants grow on millions of acres of fertile soil.
Soil that might otherwise be used to produce food.
From pure tobacco leaves,
such generally known products such as snuff, chewing tobacco, pipe tobacco, cigars, and cigarettes are made.
More stores sell tobacco than bread,
and money spent on tobacco could pay for half our schools.
This then is an example of a product that represents one of America's largest farm crops,
and one of the most controversial consumer articles.
What does this product contain and how does it affect those who use it?
What tobacco smoke contains is simple to determine.
Here is a scientifically designed apparatus
for collecting the content of the smoke under controlled conditions.
Smoking is a process of dry distillation.
By dry distillation, we mean the transformation of dry substances into vapor.
As the tobacco is smoked,
all the products normally inhaled by a smoker are collected
in these bottle traps filled with liquids.
Supplementary traps called bubblers
catch any substances not collected in the flasks.
The liquid in two of the flasks absorbs the nicotine,
and in the other two flasks it collects the tarry substances out of the burning tobacco.
From the first group of flasks, chemists isolate nicotine by distillation.
The amount of nicotine obtained in this process, is of course,
small and can only be measured by very delicate instruments.
The ultra-violet spectrophotometer for instance,
is often used to measure minute amounts of nicotine.
Different cigarettes, even of the same brand,
sometimes vary in weight and quantity of nicotine.
Variations from one to three milligrams per cigarette have been recorded.
One milligram is about this much,
and three times this amount could cause nicotine poisoning.
The liquid in the second pair of flasks contains tars.
It is first diluted with water, then chloroform is added.
The chloroform dissolves the tars from the solution.
Since chloroform and water do not mix,
the chloroform mixture separates from the water
as soon as the shaking stops.
Finally, chloroform is evaporated out of the mixture by boiling,
leaving the tars behind in the measuring cup.
Cigarette tars consist of a variety of substances,
which can be further separated chemically.
Here are some of the more important constituents of cigarette tars.
Some may be considered irritants, others, stimulants,
and some as having no known effect upon the human organism.
All smoke, including cigarette smoke,
contains some carbon monoxide,
a poisonous gas that combines readily with the hemoglobin of the red blood cells,
and prevents it from absorbing oxygen in the lungs and giving it off to the tissues.
Very little is known about how much harm carbon monoxide from smoking does.
All these tarry substances are the products of burning.
They are not in the green tobacco leaves.
But unlike tars, nicotine is found in the unburned tobacco.
In smoking, some of the nicotine enters the body.
When we light a cigarette,
about 25 percent of the nicotine is destroyed chemically by fire.
Behind the glowing tip, in the zone where tobacco is heated to a medium temperature,
gases containing nicotine arise from the leaves.
About 30 percent of these gases pass out into the atmosphere,
while the remaining 45 percent continue to flow
with the main air current towards the mouth.
However, the major portion of the nicotine does not reach the mouth.
It is deposited on the cold tobacco particles which it passes on the way.
In consequence, only some fifteen percent of the total quantity of nicotine enters the mouth.
Nicotine enters the body primarily through the air-passages and lungs.
However, some nicotine is dissolved in the saliva of the mouth and swallowed,
thus reaching the stomach directly.
From the stomach, the portal vein carries it to the liver,
where some chemical changes occur which are not yet fully understood.
But most of the nicotine enters the lungs with the inhaled air.
From the lungs, it is carried to the left side of the heart,
and from there it is rapidly distributed to all tissues of the body.
This is why the smoker feels the effects of smoking almost as soon as he lights the tobacco.
Carried by the blood, nicotine reaches the nerve cells,
where it induces a complex set of reactions.
The drug acts mainly on three parts of the nervous system:
on the ganglia, or switchboards, of the autonomic nervous system,
on the junction between nerves and the muscle, and on the brain itself.
At these points, nicotine first stimulates the nerve cells,
then gradually slows down functions and even paralyzes them.
As a consequence, many types of reactions may go on at different rates
and at different places in the body simultaneously,
producing involved and often unpredictable effects,
effects which vary with each individual.
Animal experiments enable us to observe the action of massive doses of nicotine.
Note the blood vessels in this rabbit's ear.
An injection of nicotine affects the rabbit's blood vessels dramatically.
Watch how the small arteries in the rabbit's ear gradually disappear
as the blood vessels tighten up
under the stimulating action of nicotine.
In this experimental setup,
effects of nicotine from smoking can be measured with special instruments.
Although the smoker absorbs relatively small amounts of nicotine,
sensitive instruments can record its effect.
For instance, these thermal couples record the influence of nicotine upon the body temperature.
In this experiment, we see that the skin temperature gradually drops
from .80 on the graph
to about 65, or 15 points.
The skin temperature drops because blood vessels constrict
under the influence of nicotine,
and less blood reaches the skin.
Experiments with animals help dramatize the effect of nicotine
on the nerve cells of the heart.
By applying the drug directly to the exposed nerve of a rabbit's heart,
we induce a change in rhythm.
To understand better what is happening,
let us look at a schematic drawing.
In the experiment, nicotine was applied at the spot indicated by the arrow.
And this is one nerve cell called a ganglion cell.
Nicotine first stimulates the nerve cells, then it paralyzes them.
See how the rabbit's heart first beats slower,
then speeds up as the nicotine stimulates and subsequently
paralyzes the nerve cells of the heart.
In the observation chamber,
the research scientist can measure simultaneously the action of nicotine
upon the human heart, breathing, skin temperature, and blood pressure.
The multiple graph indicates that this man's heart
has not been visibly affected by the nicotine.
The graph in the middle reproduces the pattern of breathing.
We've seen that nicotine causes the heart to beat more rapidly and often irregularly.
We've also seen that nicotine causes blood vessels to contract.
There is a connection between the two.
When the heart beats faster,
it pumps more blood through the blood vessels,
which nicotine has made narrower.
As a result, blood pressure increases.
Smoking is dangerous for persons suffering from disorders of blood vessels
of the extremities, such as in the case of Berger's disease.
To demonstrate the action of the autonomic ganglion cells of the intestines,
we place a piece of rabbit intestine in a glass container.
The rhythmic movement of the intestine continues
even after it is separated from the animal.
The scribe shows normal peristalsis.
Now we inject nicotine into the solution.
The reaction is violent.
This is one reason why doctors often advise patients
with peptic ulcers, chronic heartburn, or spastic intestines to abstain from smoking.
Nicotine also acts upon the central nervous system.
It stimulates it and produces a quickening of brain activity
which creates a feeling of nervousness and excitement.
This rabbit reacts calmly to petting and tapping.
But as soon as nicotine has acted upon it,
the rabbit reacts to the same treatment with convulsions and tremors.
Nicotine that enters the lungs of the smoker spreads rapidly through the body.
In turn it is excreted in urine, saliva, and sweat.
After several days all nicotine leaves the body,
but the urge to smoke remains.
This urge is the result of a complex set of causes,
most of them psychological.
Contrary to other habit-forming drugs,
no bad aftereffects are known to result from giving up smoking.
The question is then, why do people smoke?
[Woman 1:] It's sociable.
[Man:] I never thought why I smoke.
[Woman 2:] I started smoking when I was quite young.
[Woman 3:] My parents smoke, so do I.
[Narrator:] Most people start smoking in imitation of a hero
or because they think that it makes them look important,
grown-up, or sophisticated.
Or they just stumble into the habit.
But once formed it is a hard habit to break.
On the other hand, smoking is not an inborn, inherited, or natural urge.
Beginners almost without exception find smoking irritating.
Sometimes reactions are quite violent,
and yet smoking is a widespread social habit,
so widespread that considerable money is spent on the study of its effects.
What are the conclusions of research at this time?
For one thing, there seems to be agreement
that smoke causes irritation of air passages.
[Man coughs as smoke swirls around him.]
A smoker's cough is a well-known sound.
Of the many tar compounds in the tobacco smoke,
we cannot tell with certainty which one, or ones, cause irritation.
Our way of life makes it necessary for many people to live in air polluted
with industrial smoke, dust, and car exhaust.
Add to this the irritation of tobacco smoke
and draw your own conclusions.
Experiments with mice are being conducted in several universities.
Scientists suspect that certain constituents in the smoke,
probably some of the tarry substances,
may cause cancer in the respiratory tract,
especially in the lungs of smokers.
By smearing tars obtained from tobacco smoke and polluted city air on the skin of mice,
scientists have already succeeded in inducing cancer in mice.
Research in this area is relatively new.
Observers also point at the high incidence of lip and tongue cancers
found among pipe smokers.
The increase in heart ailments in recent years
alerted medical research to a closer observation
of smoking habits of heart patients.
There seems to be considerable agreement
about the effect of smoking upon the human organism.
But a great deal more work is needed
to explain the potentially dangerous effects of smoke tars.
Smoking is a widespread social habit,
a habit very easily acquired but very hard to break.
Helped by advertising and glamourizing, it makes new converts easily,
especially among the young.
Armed with these facts,
it must be the decision of each and every individual whether he or she
will take the risks of smoking.
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