ANEMIA Deterioration in the quality of the blood, combined often with deficiency in its quantity, is a common result in infancy and childhood of any con dition which causes a temporary failure in the nutritive processes. In the child anaemia is commonly symptomatic of some discoverable ill ; for the obscurer form, called idiopathic or pernicious anmia in the adult, is but rarely met with in early life.
The reason of the exceptional frequency of impoverishment of the blood in childhood is not difficult of explanation. From the researches of Denis, Poggiale, Wiskemann, and others, it appears that in infancy al though the quantity of blood is greater than it is in maturer life, in propor tion to the entire weight of the body, this blood is of lower specific gravity, and contains more white corpuscles, but less fibrine and soluble albumen, a smaller proportion of salts, and a considerably smaller quantity of globin.' With this comparatively dilute blood the growing child has to undertake a larger work than is required from the adult. He has to sup ply material for growth and development instead of merely maintaining the necessary nutrition of tissues and organs already matured. The heart and lungs are forced to greater efforts to answer the demands made upon them : the first to drive a sufficient quantity of blood along the relatively wider arterial channels ; the second to aerate the larger proportion of blood carried to them by the more capacious pulmonary artery. The lungs elimi nate carbonic acid in far higher proportion than is the case in older per sons. The amount of urea, too, excreted by the kidneys is relatively much greater than it is in the adult. The work required from the different se cretory and excretory organs whose united labours go to build up the growing frame may be judged from the fact that within twelve months of its birth the body has increased to three times its original weight. As Dr. Jacoby has observed, the " organs are in constant exertion, or rather over exertion, and all this at the expense of a blood which contains less solid constituents than the blood of the old.. Thus the natural oligmia of the child is in constant danger of increasing from normal physiological pro cesses. The slightest mishap reduces the equilibrium between the capital and the labour to be performed, and the chances for the diminution in the amount of blood in possession of the child are very frequent indeed."
Although the blood of the child is thus relatively poor as compared with that of the adult, a constant inflow of nutrient material enables it to preserve a healthy standard and carry on its functions with success. The amount of food consumed by the growing child is far greater proportion ately than that required by the fully developed man. According to Dr. Edward Smith, the infant as compared with the adult consumes three times as much carbon and six times as much nitrogen for every pound of his weight. If now, from any cause, either from deficiency in the supply of food, or derangement of the machinery by which food is elaborated and prepared for its purpose of nourishing and renewing the tissues the inflow fails, the standard of the blood at opce sinks below the average of health,_ and a state of anaemia or oligmnia (poorness of blood) is induced, The constituents of the blood Which are of the greatest importance in nutrition are the albuminoid compounds of the plasma and the red blood corpuscles. The albuminoid compounds constitute the material out of which the tissues are nourished ; the hmmoglobin of the red corpuscles carries the oxygen, without which the chemical changes necessary fol; nu trition are impossible. In anaemia the blood is impoverished in its iiIbu minous constituents, especially in its haemoglobin. Therefore, as the amount of iron is in direct proportion to the amount of haemoglobin, a diminution in the latter means a deficiency in the former ; and as the chief office of the is that of oxygen to the tissues, the blood in anEemia is no longer able efficiently to perform its respiratory and nutritive functions. • • Causation.—Iu early life any cause which interferes with the orderly renewal of the normal constituents of the blood leads to anaemia. In the infant—a being who is dependent for health upon a full daily supply of food—not only serious disease but even the most simple acute derange ment will leave the blood in a state of temporary oligmmia. This is usually rapidly recovered from, for in the healthy child convalescence is short, and the nutritive functions quickly resume their course when the obstacle to their proper exercise has disappeared. By amemia, however, is usually meant a more prolonged poorness of the blood—a condition in which the symptoms of general debility are allied with others indicating an imperfect performance of the bodily functions.