As animals rise in the scale, as their brains become more subtle, more elaborate in structure, their actions become correspondingly more numerous and complicated, more varied, more individual. The nervous systems of such animals are characterised by an increasing complexity of development, and this provides the machinery necessary to the performance of an increasing number of muscular and mental co-ordinations; they can adapt themselves to unfamiliar surroundings and possess much enhanced advantages in the struggle for existence. But, associated with these advantages, is a much longer period of immaturity, because, where the capacity for flexibility and progress is great, the antenatal period is insufficient for the establishment of the necessary nervous connections or even for the development of the brain cells between which these connections will be formed. The chick will have its full plumage in ten weeks, but mentally it is far below a dog or a monkey, whose period of immaturity is much longer. Similarly, the dog attains his maturity long before the monkey, who is infinitely his superior in fertility of resource, power to learn through imitation, and capacity for attention. The infant in its turn is far longer in a dependent condition than the highest ape.
Relatively large in bulk at birth, and reaching usually its full mass in the first fourteen years of life, the human brain possesses throughout childhood vast silent areas, big with future potentialities, areas in which the cells are slowly ripening to function. Even after full growth in size is reached, many more years must pass before capacity for the higher mental functions or for the complete control of such functions has developed. It must be borne in mind that, throughout this period of immaturity, errors of nutrition or defective stimulation may interfere with function. One of the most important duties of the home is to provide the suited environment for its child occupants during these long and anxious years. How long they are has been emphasised by Dr. Clouston,[106] who has said that, of all the periods of brain growth, the most important, as regards the development of our highest moral and mental potentialities, is that between eighteen and twenty-five years of age, when the capacity for self-control should be coming into function in its highest relations, and when failure to ripen in due course is fraught with most serious consequences for the future.
There is no such thing, therefore, as infancy or parental care in the lowest orders of animal life; of which, one result is a gigantic mortality among their offspring. Enormous numbers of eggs are laid to ensure the preservation of 245 the species when left to fend for themselves. The turbot, for instance, must deposit millions of minute glassy ova or the species would become extinct. Even among frogs the destruction of tadpoles is so great that provision must be made to allow for this loss. The fostering care of birds for their young at once permits a great reduction in the number of the offspring; but, though birds give evidence of some capacity for parental care, infancy, as such, is really confined to mammalian young. Even here it is curtailed in a vast number of species; but wherever it exists it stands for power to progress, and represents capacity for benefiting by, indeed depending upon, education, if only in the simple form of learning by imitation—a form familiar to readers of such books as Long’s “Schools of the Woods.”
Plasticity is the hall-mark of progress; educability indicates a brain more or less competent to assimilate, to remember, to compare, to discriminate. This door of progress has been merely set ajar for even the higher apes; it is open to man only. The period of plasticity is evidently prolonged in proportion to the degree in which conscious intelligence has superseded mere brute force in promoting successful survival—that is to say, the transmission of mental ability rather than of physical strength postpones maturity. Man alone possesses in full the powers of selection and adaptation, of reason and of emotion, of memory and of mental originality, which are 246 included in his rich heritage of life. If he is to realise his full potentialities, he must have protection for years after birth and an extended time for development. The immature infant must be fed, sheltered, and stimulated, if the inherent powers of adjustment to surroundings are to develop normally. But so great is the instability associated with human immaturity and future potentiality, that arrested development is too often the heavy penalty paid by the child for the ignorance and carelessness of his parents.[107] Faults of food and clothing, insufficient warmth, cleanliness, or exercise, premature work or precocious responsibility and independence, prolonged overstrain or insufficient stimulation of mind and body, are the prevalent causes by which a child’s normal growth is warped and prejudiced. 247 Where this occurs he never enters into his birthright of power; it has too often been thoughtlessly bartered by his natural guardians, literally for a mere mess of pottage.
X. CAUSES WHICH MENACE HEALTHFUL INFANCY AND CHILDHOOD
Perhaps one of the greatest inconsistencies of an inconsistent nation lies in the fact that the extraordinary ignorance of the elementary needs of a tender infant is not confined to one section of society; it is found in Belgravia as well as in Bermondsey. Thus, though the chief sources of the tuberculosis which is responsible for the presence of 45 per cent. of the children in the London Invalid Schools are confined to the homes of the poorer classes,[109] inquiries into the incidence of rickets among children in Glasgow show a higher percentage of cases in the families of mechanics than of labourers[110]—a clear illustration that ignorance and not poverty is here the predisposing cause. Impure air and stuffy, ill-ventilated rooms are concerned in the susceptibility to both diseases, as is also malnutrition with its associated diminution of the innate powers of self-protection. But, in the one case, inability to provide suitable food is the general cause; while in the other, 248 inexcusable ignorance of the right forms in which food should be supplied to young children is a certain source of the evil.
The thought is pathetic, for the causes are wholly preventable. Pitiful also, because less excusable, is the grievous injury to health associated with a mouth full of rotten teeth, permitted as it is among families possessed of sufficient means to meet the cost of cure, who prefer to spend their money upon dress and amusement, or among the members of which necessary endurance of a trifling shock has not been cultivated. Were the foulness of the discharge from a carious tooth to be externally visible, the æsthetic instinct among the refined would clamour for prompt treatment; but, unfortunately for health, the results of the disease are concealed, and consequently condoned.
Again: light, sunshine and quiet are now known to be essential to physical development and to the possession of a sound nervous system; the statement amounts to a platitude, for is not every wealthy invalid despatched to complete convalescence by the sea or in the country, and is not the custom of a general annual holiday due largely to the conscious benefits derived from an open-air life far from the bustle of towns? Yet physical morality is so poorly developed that the atmosphere of suburban as well as urban districts is permanently obscured by the preventable and wasteful results of imperfect combustion, though the detriment is incalculable to those whose lives see 249 no change of air. The ceaseless rumble of noisy traffic, allowed to disturb the rest of thousands, or more probably of millions, of our population, is another factor responsible for the prevalence of unstable nerves and of ill-balanced brains. It assumes great gravity when it is realised that among these sleepers are numbered the children whose hours of rest are already most seriously curtailed.
Another sin against childhood bears long enduring fruits. I refer to the terrible results upon the lives of those infants who survive efforts to prevent their birth. The fact ought to be, if it is not, common knowledge; yet the sale of the infamous drugs, necessary to the crime, by pennyworths, in every drug-store, is tacitly sanctioned by the community.