( Originally Published 1918 )
In order to understand the significance of the processes which result in intestinal toxemia or autointoxication, and the rationale of the methods by which they may be successfully combated, it is necessary to have at least an elementary knowledge of the nature of bacteria and other micro-organisms which are the active cause of the putrefactions and other changes which are known to be associated with intestinal autointoxication.
Although Pasteur was not the first to observe micro-organisms, it is chiefly to his labors that the scientific world owes its knowledge of the lowest order of plants, known in general as bacteria, or in common parlance, germs. These organisms are the lowest of all living forms. They are closely allied to fungi.
Most plants and animals consist of millions of cells associated in an organized body, each group of cells being assigned to some special duty or function. Bacteria are unicellular forms, each microbe consisting of a single cell. There are animal as well as vegetable microbes, but animal microbes are not properly called bacteria.
Bacteria differ from higher plants, not only in the fact that they are unicellular, but also in the fact that they contain no chlorophyl.
In consequence of this inability to prepare food for themselves as do the higher plants, bacteria are compelled to live a parasitic life, and like fungi, mushrooms, molds and yeast, they feed upon organic substances produced by the vital activities of higher organisms.
Bacteria have many different forms. Many bacteria appear as minute particles. These are known as "micrococci," or "cocci." When these round forms are arranged in groups having the form of strings of beads, they are termed "streptococci." Other groups having the shape of clusters are called "staphylococci." Bacteria that have the shape of long, straight rods are called "bacilli." When the rods are curved they are called "spirilla" and "vibrios."
Some bacteria have long thread-like appendages called "flagella." The flagella of bacteria make active movements by means of which the organism changes its position at a relatively rapid rate. Some organisms move a distance equal to a thousand times their length in a minute. A railroad train going at the same relative speed would travel six thousand miles an hour.
How Bacteria Grow and Work
Bacteria usually multiply by simple transverse division, a form of asexual reproduction. Recently, conjugation has been observed in certain species of bacteria. A curious form of reproduction observed in bacteria is known as auto-gamy, in which conjugation occurs between two parts of the same cell.
The rapidity with which bacteria grow is almost beyond comprehension. A single bacillus has been known to increase to four millions in half a day. Pasteur saw a single cell grow to ten millions in twenty-four hours.
The growth of germs is chiefly limited by their food supply and the destructive effects of their own excretions. Left to themselves, even with a sufficient food supply and other favorable conditions, bacteria are likely to die sooner or later killed by their own excretory products.
Bacteria consume food, as do higher plants and animals. Some bacteria require an enormous quantity of food. The energy derived from the food manifests itself as heat, which serves the chlorophyl-lacking plant in place of the heat derived from the sunlight by higher plants.
The energy set free by micro-organisms manifests itself in the heating of fermenting liquids.
The heating of green fodder in a silo and of manure in a hot bed are .examples of energy released by the activity of bacteria. Another illustration of a similar sort is found in the bacteria that fix nitrogen in the soil. The fixation of nitrogen is accomplished at the expense of the consumption of a large amount of carbohydrate, not less than two hundred pounds of carbohydrate being required for the fixing of one pound of nitrogen.
Bacteria, like all living organisms, require oxygen. Some bacteria, for example those that produce lactic acid, as in the souring of milk, obtain their oxygen directly from the air (aerobes), whereas other bacteria (anaerobes) grow without the presence of air or oxygen, and may even be destroyed by contact with atmospheric oxygen. These bacteria need oxygen, but they are so constituted that they must obtain their oxygen by breaking up compounds containing oxygen.
Certain bacteria can live and grow either in the presence of free oxygen or excluded from it.
The wonderful activity of microbes in breaking up and destroying organic substances is accomplished by means of diastases or digestive ferments, which they often produce in great quantity. Not only bacteria but yeasts and other living cells behave as ferments when deprived of oxygen.
Bacterial Toxins and Pigments
The nature of diastases is not known, but in their presence most remarkable transformations take place—such for example as are seen in the ordinary processes of digestion.
All the digestive changes that take place in the alimentary canal of man and other animals may be produced by the ferments secreted by bacteria. The action of bacteria, however, does not lead to the production of useful substances that may be employed for building up the animal body, re-pairing its tissues and supporting its activities, but is carried farther and is modified in various ways by special ferments which produce highly poisonous substances. It is in this way, for example, that the toxins of bacteria are produced. Some of these products are the result of the breaking up of the foodstuffs, and others are actual excretions of the micro-organisms.
Some of these toxins possess a degree of virulence or activity surpassing even that of the venoms of poisonous reptiles. For example, it is known that a single grain of diphtheria toxin is capable of destroying the lives of more than a thousand guinea pigs. Some toxins possess a still higher degree of virulence. A streptococcus studied by Marmormek possessed such powerful toxicity that a single grain was capable of killing seven billion rabbits.
Pigments of various sorts are produced by certain species of bacteria. Some of these are highly toxic. Deposits of these pigments in the skin produce so-called "liver spots," dinginess and bad complexion. One of the most common of these is brenzcatechin which according to Combe is formed from animal protein in the intestine, but not from vegetable protein.
Putrefaction poisons named by Brieger and Selmi, are muscarin, cholin, cadaverin, putrescin, neurin, neuridin, saprin, and others. Indol, skatol, mercaptan and other malodorous products are produced by the colon bacillus and other pernicious organisms. There are probably hundreds of poisonous products not yet identified.
Some of the most virulent toxins are produced by streptococci, the small round form of bacteria. These organisms are found constantly present in the saliva and the nasal cavity and cover the skin in countless numbers. Virulent forms often hide in crypts in the tonsils or develop into pyorrhea, a disease affecting the gums. It is now known that rheumatism, neuritis and many other painful and disabling affections are due to invasion of the body by the streptococci of the mouth.