CONTRACTILE TISSUES.-MUSCULAR CONTRACTILITY APPLICATIONS OF MUSCULAR POWER.-BONES AND JOINTS. MOTOR APPARATUS OF MAN.-SKELETON AND MUSCLES ANIMAL PHYSIOLOGY. INTRODUCTION. THE importance of the study of Animal Physiology, as a branch of General Education, can scarcely be over-estimated; and it is remarkable that it is not more generally appreciated. It might have been supposed that curiosity alone would have led the mind of Man to the eager study of those wonderful actions by which his body is constructed and maintained; and that a knowledge of those laws, the observance of which is necessary for the due performance of these actions,—in other words, for the maintenance of his health,—would have been an object of universal pursuit. That it has not hitherto been so, may be attributed to several causes. The very familiarity of the occurrences is one of these. We are much more apt to seek for explanations of phenomena that rarely present themselves, than of those which we daily witness. The Comet excites the world's curiosity, whilst the movements of the sun, moon, and planets are regarded as things of course. We almost daily see vast numbers of animals of different tribes, in active life around us; their origin, growth, movements, decline, death, and reproduction, are continually taking place under our eyes; and there seems to common apprehension nothing to explain, where everything is so apparent. And of Man too, the ordinary vital actions are so familiar, that the study of their conditions appears superfluous. To be born, to grow, to be subject to occasional disease, to decline, to die, is his lot in common with other animals; and what knowledge can avail (it may be asked) to avert the doom imposed on him by his Creator? In reply to this it is sufficient to state, that millions annually perish from a neglect of the conditions which Divine wisdom has appointed as requisite for the preservation of the body from fatal disease; and that millions more are constantly suffering various degrees of pain and weakness, that might have been prevented by a simple attention to those principles which it is the province of Physiology to unfold. From the moment of his birth, the infant is so completely subjected to the influence of the circumstances in which he is placed, that the future development of his frame may be said to be governed by them; and thus it depends, in great part, upon the care with which he is tended, and the knowledge by which that care is guided, whether he shall grow up in health and vigour of body and mind; or shall become weakly, fretful, and selfwilled, a source of constant discomfort to himself and to others; or shall form one of that vast proportion, whose lot it is to be removed from this world before infancy has expanded into childhood. The due supply of warmth, food, and air are the principal points then to be attended to; and on every one of these the greatest errors of management prevail. Thousands and tens of thousands of infants annually perish during the few first days of infancy, from exposure to cold, which their feeble frames are not yet able to resist; and at a later period, when the infant has greater power of sustaining its own temperature, and is consequently not so liable to suffer from this cause, the seeds of future disease are sown, by inattention to the simple physiological principles, which should regulate its clothing in accordance with the cold or heat of the atmosphere around. Nor is less injury done by inattention to the due regulation of the diet, as to the quantity and quality of the food, and the times at which it should be given; the rules for which, simple and easy as they are, are continually transgressed through ignorance or carelessness. And, lastly, one of the most fertile sources of infantile disease, is the want of a due supply of pure and wholesome air; the effects of which are sure to manifest themselves in some way or other, though often obscurely and at a remote period. It is physiologically impossible for human beings to grow up in a sound and healthy state of body and mind, in the midst of a close, ill-ventilated atmosphere. Those that are least able to resist its baneful influence, are carried off by the dis eases of infancy and childhood; and those whose native vigour of constitution enables them to struggle through these, become the victims, in later years, of diseases which cut short their term of life, or deprive them of a large part of that enjoyment which health alone can bring. Nor is the effect of these injurious causes confined to infancy, though most strikingly manifested at that period. "The child is father to the man," in body as well as in mind; but the vigorous health of the adult is too often wasted and destroyed by excesses, whether in sensual indulgence, in bodily labour, or in mental exertion, to which the very feeling of buoyancy and energy often acts as the incentive; and the strength which, carefully husbanded and sustained, might have kept the body and mind in activity and enjoyment to the full amount of its allotted period of "threescore years and ten," is too frequently dissipated in early manhood. Or, again, the want of the necessary conditions for the support of life, the warmth, food, and air, on which the body depends for its continued sustenance, no less than for its early development, may cause its early dissolution, even where the individual is guiltless of having impaired its vigour by his own transgressions. These statements are not theoretical merely: they are based upon facts drawn from observations carried on upon the most extensive scale. Wherever we find those conditions, which the Physiologist asserts to be most favourable to the preservation of the health of the body, most completely fulfilled, there do sickness and mortality least prevail. A few facts will place this subject in a striking light. "The average mortality of infants among rich and poor in this country (and with little variation throughout Europe) is about one in every four and a-half before the end of the first year of existence. So directly, however, is infant life influenced by good or bad management, that, about a century ago, the workhouses of London presented the astounding result of twenty-three deaths in every twentyfour infants under the age of one year. For a long time this frightful devastation was allowed to go on, as beyond the reach of human remedy. But when at last an improved system of management was adopted in consequence of a parliamentary inquiry having taken place, the proportion of deaths was speedily reduced from 2,600 to 450 in a year. Here, then, was a total of 2,150 instances of loss of life, occurring yearly in a single institution, chargeable, not against any unalterable decrees of Providence, as some are disposed to contend as an excuse for their own negligence; but against the ignorance, indifference, or cruelty of man. And what a lesson of vigilance and inquiry ought not such occurrences to convey, when, even now, with all our boasted improvements, every tenth infant still perishes within a month of its birth !” 1 The effect of attention to cleanliness and ventilation in the reduction of an excessive infantile mortality, has been equally shown in the experience of the Dublin Lying-in Hospital. At the conclusion of 1782, it was found that out of 17,650 infants born alive, no fewer than 2,944, or one in every six, had died within the first fortnight. By the more efficient ventilation of the wards, the proportion of deaths during the first fortnight was at once reduced to 419 out of 8,033, or but little more than one in twenty; and it has subsequently. been still further diminished. In the island of St. Kilda, the most northern of the Hebrides, according to the statement of a gentleman who visited it in 1838, as many as eight out of every ten children die between the eighth and twelfth day of their existence; in consequence of which terrible mortality, the population of the island is diminishing rather than increasing. This is due, not to anything injurious in the position or atmosphere of the island; for its "air is good, and the water excellent : " but to the "filth in which the inhabitants live, and the noxious effluvia which pervade their houses." The huts are small, lowroofed, and without windows; and are used during the winter as stores for the collection of manure, which is carefully laid out upon the floor, and trodden under foot, till it accumulates to the depth of several feet. The clergyman, who lives exactly as those around him do, in every respect, except as regards the condition of his house, has reared a family of four children, all of whom are well and healthy; whereas, according to the average mortality around him, at least three out of the four would have been dead within the first fortnight. It is not a little remarkable that a recent sanitary inquiry carried out by order of the Danish government, into the con 1 Dr. A. Combe on the Physiological and Moral Management of Infancy. |