The Sympathetic or Involuntary Nervous System.
The chains of the sympathetic nervous system are connected by cross branches to the sympathetic nerve ganglia on either side of the spine. It also connects by cross branches and nerve plexuses with the central nervous system or white nerve fibres. While the white nerve fibres, also called the animal nerves, are largely concerned with the voluntary acts of the body, the functions of the sympathetic, or vegetative nerves, are those concerned with the health of the body. They govern circulation, digestion and elimination, and the repair which takes place after a tissue is injured. The sympathetic nerves spread to every part of the body, especially to the vital organs. An individual who is richly supplied with nervous matter of this nature has more endurance (or vegetative force) than one who is not so endowed. While the brain and body of man wears out from the day’s work and sleep is absolutely necessary, the functions of the heart and lungs and the work of nutrition must go on just the same, but during this time the sympathetic nerves carry on the vital processes of the body without interruption. They never sleep.
CIRCULATION.
The blood is a circulatory fluid and is pumped by the heart through the arteries to every part of the body. The arteries are elastic tube-like canals with walls consisting of fibrous material and are lined by delicate muscular layers. The arteries in their distribution communicate freely with one another, dividing and sub-dividing, becoming continually smaller, until they can no longer be traced by the naked eye. These smallest branches are called capillaries. It is by means of them that metabolism becomes possible. The nutriment of the blood passes out through their walls into the tissues and the waste from the tissues passes back into the blood. These unite forming larger vessels called veins which carry the waste matter back to the heart and lungs. The color of the venous blood is dark blue while that of the arteries is bright red.
The Lymphatics.
The lymphatic system consists of lacteals, glands and lymphatic vessels. The lacteals are small vessels originating in the villi of the small intestine side by side with the blood vessels. They contain the milk-white fluid called chyle. The lymphatic vessels, like the arteries and veins, are tubular canals, lined with delicate muscular layers and membrane. They unite with each other, gradually forming larger vessels. In their course they pass through numerous lymphatic glands and finally unite into two great trunks.
Sunlight is a great disinfectant. Dark rooms are a breeding place for tuberculous germs. Daily out of door exercise in the sunshine will increase health and reduce the coal bill. Without exercise our food can be of little benefit to us.
Absorption.
The alimentary tract with its different departments resembles somewhat a manufacturing plant. The first of these departments is the mouth. When mastication and insalivation are completed, the food is conveyed by deglutition to the stomach. Here it is subjected to churning and chemical changes by the involuntary muscles and the secretion of the gastric juice. When this is accomplished, the contents pass into the intestine. Here they mingle with fluids secreted by the gall bladder and pancreas. Food which has been reduced to chyme by the stomach is now reduced to chyle or liquefied food and is absorbed by the lacteals. When the digested material is absorbed and carried to the liver, the glands and other blood making organs, the process is called sanguification. From there the blood is carried to the heart and lungs to receive oxygen and then it is distributed to the different organs and tissues of the body. These processes are directed by the intelligence of the sympathetic nervous system which therefore governs the nutrition of the central nervous system, known as the animal nerves. Space is too limited to go into a discussion of the functional activities of the different ductless glands and their relation to the tissue metabolism.
Drink sufficient pure natural water between your meals. There is danger in over-drinking as well as in under-drinking.