A Treatise on Anatomy, Physiology, and Hygiene Part 12

177. _Relaxation must follow contraction, or, in other words, rest must follow exercise._ The necessity of relaxation, when a muscle has been called into action, is seen in the example of a boy extending his arm with a book in his hand, as a penalty. The boy can keep the arm extended but a short time, make what effort he may. It is also seen in the restlessness and feverish excitement that are evinced by persons gazing on troops during days of review. The same is noted in shopping.

Such employments call into action the muscles that support the spinal column in an erect position, and the languor or uneasiness is muscular pain. The long-continued tension of a muscle enfeebles its action, and eventually destroys its contractility.

178. _In school, the small children, after sitting a short time, become restless._ If their position be changed, their imperfectly developed muscles will acquire tone, and will again support the spinal column erect without pain. The necessity for frequent recesses in school, is founded on the organic law of muscular action alternating with rest. The younger and feebler pupils are, the greater the necessity for frequent recesses. We would not have the teacher think that one half of the time should be spent in recesses; or the mother, that her daughter is going to school to play. But we do maintain that recesses should be given, and that they should be short and frequent, especially for small and feeble scholars.

179. _Exhaustion is the inevitable result of continued muscular contraction._ For example, let a lady ply the needle quickly for some hours, and the muscles of the back and right arm will become exhausted, which will be indicated by a sense of weariness in these parts. A change of employment and position calls into action a different set of muscles, and the exhausted organs are relieved.

177. What is said of the contraction and relaxation of the muscles?

Give examples of the necessity of relaxing the muscles. 178. Why should not small children be confined in one position for a long time?

What evils result from this practice? What cla.s.s of pupils should have recesses most frequently? 179. What effect has continued muscular contraction?

180. _Much more labor will be accomplished by taking time to relax the exhausted muscles_, or by so changing the employment as to bring into action a new set of muscles; the woodman thus relieves himself, by sawing and splitting alternately. This principle applies to the labor of the horse and ox; and it is also applicable to all kinds of employment. With the invalid convalescing from fever, relapses result from inattention to these laws. When a patient is recovering from sickness, his physician should take care that his exercise be proper, neither too much, too little, nor too long continued.

181. _The muscles of growing youths will not endure so much exercise or labor as those of mature men._ In youth a portion of the vital, or nervous energy of the system, is expended upon the growth of the organs of the body, while in the individual who has attained his growth, this expenditure is not demanded; consequently severe labor or exercise should not be imposed on growing children.

_Observation._ In the campaigns of Napoleon Bonaparte, his army was frequently recruited by mere boys. He complained to the French government, because he was not supplied with men of mature years, as the youths could not endure the exertion of his forced marches.

182. _The muscles should be gradually called into action._ These organs in action require more blood and nervous fluid than when at rest. As the circulation of these fluids can only be increased in a gradual manner, it follows, that, when the muscular system has been in a state of rest, it should not suddenly be called into vigorous action. On arising from a bed, lounge, or chair, the first movements of the limbs should be slow, and then gradually increased.

_Observation._ if a man has a certain amount of work to perform in nine hours, and his muscles have been in a state of rest, he will do it with less fatigue by performing half the amount of the labor in five hours, and the remainder in four hours. The same principle should be regarded in driving horses and other beasts of burden.

180. How can the greatest amount of labor be secured with the least exhaustion to the muscles? 181. Why should not severe labor be imposed on growing children? 182. How should the muscles be called into action?

183. _The muscles should be rested gradually, when they have been vigorously used._ If a person has been making great muscular exertion in cutting wood, or any other employment, instead of sitting down to rest, he should continue muscular action, for a short time, by some moderate labor or amus.e.m.e.nt.

184. _If the system has been heated by muscular action, and the skin is covered with perspiration, avoid sitting down_ "to cool" in a current of air; rather, put on more clothing, and continue to exercise moderately. In instances when severe action of the muscles has been endured, bathing and rubbing the skin of the limbs and joints that have been used, are of much importance. The laboring agriculturist and industrious mechanic, by reducing to practice this suggestion, would thus prevent soreness of the muscles, and stiffness of the joints.

185. _The muscles should be abundantly supplied with pure blood._ This state of the circulating fluid requires a healthy condition of the digestive apparatus, and that the skin should be kept warm by proper clothing, clean by bathing, and be acted upon by pure air and good light; the movements of the ribs and diaphragm should be unrestricted, and the lungs should have ample volume and be supplied with pure air.

In all instances, muscular power is greatest when the preceding conditions exist, as the muscles are then stimulated by pure blood; consequently, it is of practical importance to the mechanic, the farmer, the man of leisure, and not less so to the ladies, to observe these conditions, whatever vocation of life they pursue.

183. How should the muscles be rested when they have been vigorously used? 184. What precaution is given when the skin is covered with perspiration? How may soreness of the muscles, consequent upon severe action, be prevented? 185. Should the muscles be supplied with pure blood? When is muscular power the greatest?

186. _The muscles should be used in pure air._ The purer the air we breathe, the more stimulating the blood supplied to the muscles, and the longer they can be used in labor, walking, or sitting, without fatigue and injury; hence the benefit derived in thoroughly ventilating all inhabited rooms. For the same reason, if the air of the sick-room is pure, the patient will sit up longer than when the air is impure.

_Observation._ It is a common remark that sick persons will sit up longer when riding in a carriage, than in an easy chair in the room where they have lain sick. In the one instance, they breathe pure air; in the other, usually, a confined, impure air.

187. _The muscles should be exercised in the light._ Light, particularly that of the sun, exercises more or less influence on man and the inferior animals as well as on plants. Both require the stimulus of this agent. Shops occupied by mechanics, kitchens, and sitting-rooms, should be well lighted, and situated on the sunny side of the house. Cellar kitchens and underground shops should be avoided.

For similar reasons, students should take their exercise during the day, rather than in the evening, and, as much as possible, laborers should avoid night toil.

_Ill.u.s.trations._ Plants that grow in the shade, as under trees, or in a dark cellar, are of lighter color and feebler than those that are exposed to the light of the sun. Persons that dwell in dark rooms are paler and less vigorous than those who inhabit apartments well lighted, and exposed to the rays of the sun.

186. Why should the muscles be used in pure air? Give a common observation. 187. What effect has light on the muscular system? What should the laborer avoid? Why should not students take their daily exercise in the evening? How is the influence of solar light ill.u.s.trated?

188. _Exercise should be regular and frequent._ The system needs this means of invigoration as regularly as it does new supplies of food. It is no more correct that we devote several days to a _proper_ action of the muscles, and then spend one day inactively, than it is to take a _proper_ amount of food for several days, and then withdraw this supply for a day. The industrious mechanic and the studious minister suffer as surely from undue confinement as the improvident and indolent. The evil consequences of neglect of exercise are gradual, and steal slowly upon an individual. But sooner or later they are manifested in muscular weakness, dyspepsia, and nervous irritability.

_Observation._ The custom among farmers of enduring severe and undue toil for several successive days, and then spending one or two days in idleness to _rest_, is injudicious. It would be far better to do less in a day, and continue the labor through the period devoted to idleness, and then no rest will be demanded.

189. _Every part of the muscular system should have its appropriate share of exercise._ Some employments call into exercise the muscles of the upper limbs, as shoe-making; others, the muscles of the lower limbs; while some, the muscles of both upper and lower limbs, with those of the trunk, as farming. In some kinds of exercise, the lower limbs are mainly used, as in walking; in others, the upper limbs; and again, the muscles of the trunk, together with those of the upper and lower limbs, as in archery, quoits, playing ball. Those trades and kinds of exercise are most salutary, in which all the muscles have their due proportion of action, as this tends to develop and strengthen them equally. Thus labor upon the farm and domestic employment are superior as vocations, and archery, quoits, and dancing, if the air is pure, among the pastimes. For sedentary persons, that kind of exercise is best which calls into action the greatest number of muscles.

188. How should exercise be taken? What is said respecting irregular exercise? Are the consequences of neglected exercise immediately apparent? What practical observation is given? 189. Should every muscle have its due amount of exercise? Mention some employments that only call into action the muscles of the upper limbs. Those of the lower limbs, those of the trunk and limbs. Mention, in the different pastimes, what muscles are called into action.

190. _The proper time for labor or exercise should be observed._ This is modified by many circ.u.mstances. As a general rule, the morning, when the air is pure and the ground dry, is better than the evening; for then, the powers of the body are greatest. Severe exercise and labor should be avoided immediately before or after eating a full meal, for the energies of the system are then required to perform the digestive function. For similar reasons, it is not an appropriate time for energetic muscular action immediately before or after severe mental toil, as the powers of the system are then concentrated upon the brain.[6]

[6] It appears to be a fact, that no two important organs can be called into intense action at the same time, without injury to both, as well as to the general system. This arises from the circ.u.mstance that an organ, when in functional action, attracts fluids (sanguineous and nervous) from other organs of the system. Except in a few instances of high health in youth, the power of the system is not adequate to supply more than one organ in action with the appropriate fluids at the same time.

What kinds of exercise are best? 190. What rule is given respecting the time for exercise? 191. Why do the muscles require sleep? What is the effect of an inversion of the law of rest?

191. _The muscles require sleep to restore their expended energies._ Among the arrangements of creative wisdom, no one harmonizes with the wants of the system more than the alternation of day and night. The natural inclination of man to sleep, is in the stilly hour of night, when all nature reposes, and to be in action during the light of day.

An inversion of this law of rest causes greater exhaustion of the system than the same amount of exertion during daylight. This is ill.u.s.trated by the wearied and exhausted condition of watchers, night-police, and other individuals who spend a part of the night in some active business of life.

192. _The muscles should not be compressed._ Compression prevents the blood from pa.s.sing to the muscles with freedom; consequently, they are not supplied with material to renovate and promote their growth.

Again, pressure stimulates the lymphatics to action; and by the increased activity of these vessels the muscles are attenuated. In the case of a man with a fractured limb, the muscles are not only enfeebled by inaction, but diminished in size by compression from the dressing. Limbs enfeebled in this way will not recover their size, tone, and strength, until the bandages are removed, and a proper amount of exercise taken.

193. The pressure of tight dresses, under the name of a "snug fit,"

enfeebles the muscles of the back, and is a common cause of projecting shoulders and curvature of the spinal column. Thus every appendage to the dress of ladies which prevents free motion of the muscles of the chest and spinal column, weakens the muscles thus restrained, and not only prevents the proper expansion of the lungs, but, by weakening the muscles which sustain the spine, induces curvature and disease.

Whalebone, wood, steel, and every other unyielding substance, should be banished from the toilet, as enemies of the human race.

194. _The mind exerts a great influence upon the tone and contractile energy of the muscular system._ A person acting under a healthy mental stimulus will make exertion with less fatigue than he would without this incentive. For this reason, a sportsman will pursue his game miles without fatigue, while his attendant, not having any mental stimulus, will become weary. Again, if the sportsman spends some hours in pursuit of his favorite game without success, a feeling of languor creeps over him; but while he is thus fatigued and dispirited, let him catch a glimpse of the game,--his wearied feelings are immediately dissipated, and he presses on with renewed energy and recruited strength.

192. Why should not the muscles be compressed? 193. What is the effect of tight clothing upon the muscles? 194. What is said of the influence of the mind upon muscular activity? Give an ill.u.s.tration of mental stimulus coperating with muscular activity in the case of a sportsman.

195. This principle was well ill.u.s.trated in the retreat from Russia of the defeated and dispirited French army. When no enemy was near, they had hardly strength sufficient to carry their arms; but no sooner did they hear the report of the Russian guns, than new life seemed to pervade them, and they wielded their weapons powerfully until the foe was repulsed, then there was a relapse to weakness, and prostration followed. It is thus with the invalid when riding for his health;--relate an anecdote, or excite this mental stimulus by agreeable conversation, and much benefit will accrue from the ride to the debilitated person. So it is in the daily vocations of life; if the mind have some incentive, the tiresomeness of labor will be greatly diminished. Let an air of cheerfulness ever pervade our every employment, and, like music, "it sweetens toil."