[Sidenote: Bacteria chief causes of abnormal changes]
Under this heading we will consider the chemical changes which take
place in the human alimentary canal, which are not beneficial or
necessary to normal digestion. The cause of the most important abnormal
changes in the contents of the stomach and the intestines is the
presence of living micro-organisms called bacteria.
In the lesson entitled "Evolution of Man," a general survey of the
history of man's development from lower forms of life is given. In this
general work I do not elaborate extensively upon the method by which
evolution proceeds, but those who are acquainted with the writings of
Darwin, and other evolutionists, are familiar with the phrases "the
survival of the fittest," and "the struggle for existence."
[Sidenote: "Survival of the fittest" among bacteria]
As we commonly think of "the survival of the fittest" in animal life, we
picture the death-struggle of the captured animal, or the fight for food
in times of scarcity, or, if it be in the case of plants, the crowding
or the struggling for soil and sunlight. We can apply the same principle
to bacteria and to other microscopic forms of life.
Bacteria, while minute masses of unconscious protoplasm, are, by the
laws of growth and reproduction, struggling for existence just as truly
as are the more conspicuous forms of life.
Because of the invariable presence of greater or less quantities of
bacteria within the intestines of all ordinary animals, some scientists
insist that their presence is in some way necessarily related to the
life of the animal, and is probably beneficial.
[Sidenote: Experiments proving accumulation of bacteria]
New-born animals, however, are free from bacteria, and the bacterial
germs found in the more matured animal must, therefore, have been taken
into the alimentary canal with food. Ingenious scientists have taken
new-born guinea pigs, and have kept them in sterile or germ-proof
compartments, giving them filtered air to breathe, and absolutely
sterile food. These pigs lived and thrived through the experiment as did
their fellows outside the bacterial-proof dwelling. This is considered
good evidence that bacteria accumulate in the digestive organs of all
animals, not for a purpose connected with animal physiology, but because
in order to digest and to assimilate food, conditions are established
which are so nearly like those required for bacterial growth, that
bacteria are produced, or take advantage of the favorable conditions,
just as weeds, if given a chance, thrive in a cultivated field.
[Sidenote: Not all bacterial growth is harmful]
I have already referred to the antiseptic or germ-destroying properties
of the gastric juice, and to other secretions of the digestive organs.
This would suggest that the growth of bacteria is undesirable from the
standpoint of man's welfare. There are many species of bacteria growing
in the human intestines, hence we cannot say with certainty that all
this bacterial growth is harmful, as, in order to determine this, the
resulting waste-products of each particular species of bacteria would
need to be considered separately. We can, however, make the general
statement that bacteria are abnormal, or foreign to the human digestive
canal, and that their presence is detrimental to human welfare.
Micro-organisms give off various substances as waste-products of their
growth, dependent upon the species of bacteria, and the material in
which they are growing. Thus the waste-products of the yeast-plant are
carbon dioxid and alcohol.
[Sidenote: Waste-products of bacterial fermentation]
In the alimentary canal there exists an abundance of carbohydrate and
proteid substances which form excellent food material for numerous
species of bacteria. The substances produced by the growth of these
various kinds of bacteria are numerous. They include the gases, carbon
dioxid, hydrogen, hydrogen sulfid, marsh-gas or methane, and ammonia.
Butyric, lactic, and other acids, together with alcohol, are also
produced as a product of bacterial fermentation in the intestines.
Perhaps the most detrimental of all are the substances produced by the
bacterial putrefaction of proteids, of which indol and skatol are the
two most important.
[Sidenote: Solubility and distribution of bacterial waste-products]
Under ordinary conditions the bacteria themselves do not penetrate
the intestinal walls, and their evil influence would be confined to
mechanical disturbance of gas in the digestive organs, and to the
destruction of a portion of the nutritive material of food, were it not
for the fact that these harmful and poisonous waste-products I have
mentioned, are soluble, and hence pass through the intestinal walls with
the digested food material, into the blood, and are thus distributed
throughout the body.
It has been observed in the presence of intestinal congestion, where
the food lies in the intestines for an abnormally long period, that the
amount of these harmful nitrogenous decomposition products excreted by
the kidneys, is considerably increased, proving that these products have
circulated throughout the body.
[Sidenote: Causes of hardening of the arteries]
Arterio-sclerosis, or the hardening of the walls of the arteries, which
has for many years been recognized by scientists as one of the principal
causes of old age, comes from two causes:
(1) The over-consumption of starchy foods, especially of the
cereal group; and (2) by the continued presence, in the blood, of
small quantities of poisonous material which gradually destroys the
protoplasm of the arterial walls, and causes them to be replaced by
a degenerate form of tissue.
For example, alcohol and the poison of syphilis are prolific causes of
the hardening of the arteries. If the diet were balanced so as to avoid
excesses of starch and these toxic substances, the hardening of the
arteries would not take place.
[Sidenote: Overeating an ultimate cause of old age]
The poisons produced in the intestines by bacterial decomposition,
superinduced largely by overeating, are absorbed into the blood,
and undoubtedly their action is similar to the other poisons herein
mentioned. Thus they become a most potent factor in the cause of old age
and premature death, being practically universal among all civilized
tribes.
Numerous other disorders or dis-eases can be traced to this same general
cause, and the subject of the poisonous products of fermentation and
decomposition in the intestines will therefore be constantly referred to
throughout this work.
[Sidenote: The growth of bacteria decreased by scientific eating]
From the deductions that have been made it is clearly evident that any
system of feeding which will reduce the amount of bacterial growth in
the intestines, would be desirable and beneficial to mankind, while
foods and habits of life that increase the amount of such poisons are to
be guarded against as detrimental to both health and life.
[Sidenote: Overeating primary cause of fermentation]
Overeating is perhaps the greatest of all dietetic errors in bringing
about a condition which favors excessive intestinal fermentation.
Overeating causes stomach prolapsus, thus reducing its mixing or
peristaltic activity. This retards the process of emptying, called
digestion, which is the primary cause of fermentation. Under this
condition the antiseptic properties of the stomach-juices are reduced,
and the bacteria from the fermenting food is vastly increased. The
food, passing from the stomach in a fermenting state, produces gas in
the intestines, with the resultant ills that follow, such as vertigo,
dizziness, irregular heart action, and usually intestinal congestion or
constipation.