The bones during life are constantly going through the process of absorption and reconstruction. They are easily modified in their growth. Thus the continued pressure of some morbid deposit, as a tumor or cancer, or an enlargement of an artery, may cause the absorption or distortion of bones as readily as of one of the softer tissues. The distortion resulting from tight lacing is a familiar illustration of the facility with which the bones may be modified by prolonged pressure.
Some savage races, not content with the natural shape of the head, take special methods to mould it by continued artificial pressure, so that it may conform in its distortion to the fashion of their tribe or race. This custom is one of the most ancient and widespread with which we are acquainted. In some cases the skull is flattened, as seen in certain Indian tribes on our Pacific coast, while with other tribes on the same coast it is compressed into a sort of conical appearance. In such cases the brain is compelled, of course, to accommodate itself to the change in the shape of the head; and this is done, it is said, without any serious result.
59. Sprains and Dislocations. A twist or strain of the ligaments and soft parts about a joint is known as a sprain, and may result from a great variety of accidents. When a person falls, the foot is frequently caught under him, and the twist comes upon the ligaments and tissues of the ankle. The ligaments cannot stretch, and so have to endure the wrench upon the joint. The result is a sprained ankle. Next to the ankle, a sprain of the wrist is most common. A person tries, by throwing out his hand, to save himself from a fall, and the weight of the body brings the strain upon the firmly fixed wrist. As a result of a sprain, the ligaments may be wrenched or torn, and even a piece of an adjacent bone may be torn off; the soft parts about the injured joint are bruised, and the neighboring muscles put to a severe stretch. A sprain may be a slight affair, needing only a brief rest, or it may be severe and painful enough to call for the most skillful treatment by a surgeon. Lack of proper care in severe sprains often results in permanent lameness.
A fall or a blow may bring such a sudden wrench or twist upon the ligaments as to force a bone out of place. This displacement is known as a dislocation. A child may trip or fall during play and put his elbow out of joint. A fall from horseback, a carriage, or a bicycle may result in a dislocation of the shoulder joint. In playing baseball a swift ball often knocks a finger out of joint. A dislocation must be reduced at once. Any delay or carelessness may make a serious and painful affair of it, as the torn and bruised parts rapidly swell and become extremely sensitive.
60. Broken Bones. The bones, especially those of the upper limbs, are often fractured or broken. The simple fracture is the most common form, the bone being broken in a single place with no opening through the skin. When properly adjusted, the bone heals rapidly. Sometimes bones are crushed into a number of fragments; this is a comminuted fracture. When, besides the break, there is an opening through the soft parts and surface of the body, we have a compound fracture. This is a serious injury, and calls for the best surgical treatment.
A bone may be bent, or only partly broken, or split. This is called "a green-stick fracture," from its resemblance to a half-broken green stick. This fracture is more common in the bones of children.
Fractures may be caused by direct violence, as when a bone is broken at a certain point by some powerful force, as a blow from a baseball bat or a fall from a horse. Again, a bone may be broken by indirect violence, as when a person being about to fall, throws out his hand to save himself. The force of the fall on the hand often breaks the wrist, by which is meant the fracture of the lower end of the radius, often known as the "silver-fork fracture." This accident is common in winter from a fall or slip on the ice.
Sometimes bones are broken at a distance from the point of injury, as in a fracture of the ribs by violent compression of the chest; or fracture may occur from the vibration of a blow, as when a fall or blow upon the top of the head produces fracture of the bones at the base of the brain.[6]
61. Treatment for Broken Bones. When a bone is broken a surgeon is needed to set it, that is, to bring the broken parts into their natural position, and retain them by proper appliances. Nature throws out between and around the broken ends of bones a supply of repair material known as plastic lymph, which is changed to fibrous tissue, then to cartilage, and finally to bone. This material serves as a sort of cement to hold the fractured parts together. The excess of this at the point of union can be felt under the skin for some time after the bone is healed.
With old people a broken bone is often a serious matter, and may cripple them for life or prove fatal. A trifling fall, for instance, may cause a broken hip (popularly so called, though really a fracture of the neck of the femur), from the shock of which, and the subsequent pain and exhaustion, an aged person may die in a few weeks. In young people, however, the parts of a broken bone will knit together in three or four weeks after the fracture is reduced; while in adults, six or even more may be required for firm union. After a broken bone is strong enough to be used, it is fragile for some time; and great care must be taken, especially with children, that the injured parts may not be broken again before perfect union takes place.[7]
62. The Effect of Alcohol upon the Bones. While the growth of the bones occurs, of course, mainly during the earlier years of life, yet they do not attain their full maturity until about the twenty-fifth year; and it is stated that in persons devoted to intellectual pursuits, the skull grows even after that age. It is plainly necessary that during this period of bone growth the nutrition of the body should be of the best, that the bones may be built up from pure blood, and supplied with all the materials for a large and durable framework. Else the body will be feeble and stunted, and so through life fall short of its purpose.
If this bony foundation be then laid wrong, the defect can never be remedied. This condition is seen in young persons who have been underfed and overworked. But the use of alcoholic liquors produces a similar effect, hindering bone cell-growth and preventing full development.[8] The appetite is diminished, nutrition perverted and impaired, the stature stunted, and both bodily and mental powers are enfeebled.
63. Effect of Tobacco upon the Bones. Another narcotic, the destructive influence of which is wide and serious, is tobacco. Its pernicious influence, like that of alcohol, is peculiarly hurtful to the young, as the cell development during the years of growth is easily disturbed by noxious agents. The bone growth is by cells, and a powerful narcotic like tobacco retards cell-growth, and thus hinders the building up of the bodily frame. The formation of healthy bone demands good, nutritious blood, but if instead of this, the material furnished for the production of blood is poor in quality or loaded with poisonous narcotics, the body thus defrauded of its proper building material becomes undergrown and enfeebled.
Two unfavorable facts accompany this serious drawback: one is, that owing to the insidious nature of the smoky poison[9] (cigarettes are its worst form) the cause may often be unsuspected, and so go on, unchecked; and the other, that the progress of growth once interrupted, the gap can never be fully made up. Nature does her best to repair damages and to restore defects, but never goes backwards to remedy neglects.
Additional Experiments.
Experiment 11. Take a portion of the decalcified bone obtained from Experiment 4, and wash it thoroughly in water: in this it is insoluble. Place it in a solution of carbonate of soda and wash it again. Boil it in water, and from it gelatine will be obtained.
Experiment 12. Dissolve in hydrochloric acid a small piece of the powdered bone-ash obtained from Experiment 3. Bubbles of carbon dioxid are given off, indicating the presence of a carbonate. Dilute the solution; add an excess of ammonia, and we find a white precipitate of the phosphate of lime and of magnesia.
Experiment 13. Filter the solution in the preceding experiment, and to