p. 101 | PRACTICAL HYDROTHERAPY by C. E. Stewart

Seventh-day Adventist Publishing Association · Battle Creek, Mich. · Feb 18, 1902

PRACTICAL HYDROTHERAPY.

By C. E. Stewart

Lesson 1—Some Principles of Physiology.

The necessity of a knowledge of the principles of physiology is recognized by comparatively few persons, yet the subject is one which should form the basis of our common-school education.

What can be of more importance than a knowledge of the structure of the human body and of the laws governing “the masterpiece of God’s created works”? Much of the time spent in the study of subjects which are of comparatively little value to the majority of students, could be more profitably spent in the study of physiology and allied subjects. Such a study should not be taken up simply for the purpose of storing the brain with a multitude of facts, but with the object of putting the knowledge to immediate and practical use. There are many persons who spend much time in studying how to prevent their cattle from becoming consumptive, their hogs from contracting hog cholera, and other things of a similar nature, but who scarcely give a thought as to how they can protect their children or themselves from disease.

Every man, woman, and child should be taught the principles of physiology and hygiene, which will enable them better to care for themselves, to prevent sickness, and to employ simple and effective remedies intelligently.

God’s laws are fixed laws wherever found, whether it be in the spiritual or in the physical world; consequently principles can be based upon these laws, which are as fixed and eternal as the laws themselves. The acorn as we find it in the forest has no semblance whatever to the tree from which it has fallen, yet it contains within itself the principles which, when placed in proper surroundings, will develop into a tree of the same species as that from which it dropped. The kernel of wheat, when placed in the ground, germinates, grows, and brings forth other grains of wheat. The acorn never yields a maple, or the kernel of wheat one of barley, because in the beginning God established a law which decreed that an acorn should bring forth an oak, and a kernel of wheat should bring forth wheat: so it is throughout all nature. “After his kind.”

The human body, like the acorn, springs from a seed of miniature size as compared with the parent, and in this seed are stored the principles which are to develop into a complete human being.

This miniature organism, about 1/20 of an inch in diameter, so small that it is difficult to detect it with the naked eye, is spherical in shape, and contains within an outer covering a small body called a nucleus. The whole is called an ovum, or egg, and when it is placed under proper environments, it begins to enlarge, and the nucleus divides into two equal parts; each one of these again divides into two other parts, making four in all. This process of division is kept up until the whole mass, which has become much larger by this time, is so entirely filled with these little spherical cells that it looks like a mulberry. After this a cavity begins to develop in the midst of the cells, and the latter are crowded principally to one side of the sphere, forming an outer and an inner layer; a third layer is soon formed between the first two, and from these three layers every structure of the human body is developed. From the outer layer, or epiblast, the outer skin and nervous system are the chief structures; from the middle layer, or mesoblast, the framework of the body, blood and blood-vessels, and the cells lining the closed cavities of the body; from the lower layer, or hypoblast, the lining of the respiratory and digestive tract.

Attention is called to this for the purpose of bringing out clearly the close association existing between the skin of the body and the nervous system. The nervous system being developed from the same layer as the skin, at once calls attention to the fact that a very close relationship exists between them. This close relationship, however, exists not only between the skin and the nervous system, but between all structures of the body and the nervous system. If it were possible to remove every vestige of tissue from the body, with the exception of the nervous system, we should have, as far as the shape of a human body is concerned, a perfect shape, for every part of the body is full of nerves.

The function of the nervous system is to harmonize and control the various functions of the body. It is divided into two parts: the Central nervous system, consisting of the brain and its nerves, and the spinal cord and its nerves; and the sympathetic system, consisting of a large number of small masses of nerve tissue located on either side, and in front of the spinal cord, and others located in the involuntary muscles of the blood vessels, intestines, and other structures of the body, all of which are joined together by innumerable fibers. The central nervous system governs the voluntary functions of the body, while the sympathetic system governs the involuntary functions. A brief explanation of the anatomy and physiology of these two systems will make clear some important points.

In the first place, the brain is the chief center. In it ideas originate, and plans for execution of movements, etc., are carried out. The nerve tissue proper consists of nerve fibers and nerve cells. The fiber being simply a prolongation of the nerve cell, the whole is called a neuron. This neuron is capable of originating impulses in its cell which are transmitted to remote parts by means of the fiber. For instance, we observe through the sense of sight, some beautiful object, and wish to become more familiar with it. The idea is conceived in the brain that to do so we must handle it; consequently, the impulses generated within the cells of the brain travel to the muscles, which in turn make the necessary movements to enable us to handle the object. There are two kinds of impulses conveyed by these fibers: that which travels from the outside, as from the skin, eye, ear, or any other sensory organ, and is called a sensory impulse; another, which travels from the brain and spinal cord to the muscles, glands, blood vessels, etc., and is called a motor impulse.

The brain is the chief center where these sensory impulses terminate, and from which the motor impulses start. It is made up of innumerable cells and fibers which convey impulses in all directions, over the spinal cord. The spinal cord is made up of pathways consisting of fibers, some carrying impulses from the skin to the brain, others from the brain to the skin, muscles, blood vessels, etc.

The skin is the great sensory organ of the body. The point of a pin cannot be placed upon it without the stimulation of a sensory nerve. These motor and sensory fibers leave the spinal cord in two bundles, or roots; the one leaving the back part of the cord contains the sensory fibers, while the other, leaving the front part, contains the motor fibers. Soon after leaving the cord, these roots join each other, and form a spinal nerve, which passes to its own area of skin, muscle, etc. There are thirty-one pairs of these spinal nerves supplying the various parts of the body with motor and sensory nerves. The brain also sends out twelve pairs of nerves which perform similar functions.

This part of the nervous system, which has been so briefly described, controls the voluntary functions of the body; that is, the functions that are governed by the will. The sympathetic system, which is intimately connected with this system, and is readily influenced by it, has for its function the governing of the involuntary functions of the body, such as the heart-beat, size of the blood vessels, digestion, secretions, and numerous others over which the will has very little, if any, control.

Through the close relationship existing between the central nervous system and the sympathetic system a harmonious action is maintained between the voluntary and the involuntary actions. For instance, when we run, which is a voluntary act, the heart beats faster, and we breathe faster—both involuntary acts—in order that the rapidly working muscles may have a sufficient supply of pure, fresh blood with which to carry on the additional work they have to do in the act of running.

From a knowledge of the foregoing facts, coupled with previous observations, it is not difficult to see how the various functions of the body are readily controlled by impressions made upon the nervous system. It is through influences acting upon the sensory nervous system that most of these changes are brought about. The skin being the greatest sensory organ of the body, it becomes naturally the one through which the most effective influence can act. As an illustration of this, we call attention to the fact that the normal body temperature remains the same in winter as in summer, and the same whether we are in a room at 70°, or out of doors at 20° below zero.

One naturally inquires, How is this equilibrium of temperature maintained?—When the cold atmosphere strikes the skin, the sensory nerves convey impulses to the spinal cord and brain, making known the fact that the temperature is falling; upon receipt of this information, motor impulses are at once sent to the muscles of the blood vessels of the skin, causing them to contract, thereby lessening the amount of heat eliminated from the skin. Impulses are also sent to the tissues in which oxidation is going on, causing a more rapid formation of heat. Thus through the decreased heat elimination and increased heat production brought about through impulses started in the skin, the normal bodily temperature of 98.6° is maintained.

C. E. STEWART, M. D. (Continued next week.)