The causes of such a condition may be divided into two classes, accord ing as to whether they interfere with the continued renovation of the blood or abnormally increase its consumption.
In the first class are included all the various conditions which hinder the introduction and elaboration of nutritive material. Thus, actual defi ciency of food, such as arises from extreme poverty or wilful neglect ; an unsuitable diet, the stomach being loaded with food which, from its nature or form, is beyond the child's power of digestion ; functional derangements of the gastrointestinal canal, owing to which an otherwise suitable food is rendered temporarily inappropriate—these causes may prevail at all periods of childhood, but are especially frequent during the period of infancy ; and the anemia and wasting which are so common in hand-fed babies can usually be referred to the action of these agencies. To them must be added the influence of imperfect ventilation. Oxygen is as essen tial to healthy tissue change as are the elements of food themselves, and in its absence the chemical changes necessary for the renewal and develop ment of the tissues are impossible. Consequently infants confined to close, ill-ventilated rooms are pale and flabby, however carefully their dietary may be adjusted.
The above causes are also powerful to impede nutrition and promote the impoverishment of the blood after the period of infancy has gone by. The influence of digestive derangements, combined or not with want of fresh air and exercise, is one of the commonest causes of anemia in later childhood. The causes which induce impoverishment of the blood are no doubt often complex ; but of such as act alone imperfect digestion from catarrh of the stomach is perhaps to be blamed more often than any other injurious condition. These attacks tend to be repeated, and, as is else where explained, recurring gastric catarrh may induce a degree of pallor and wasting which excites the greatest alarm in the minds of the parents, and often requires very careful treatment for its prevention and cure (see Gastric Catarrh).
Again, the diathetic diseases—tuberculosis, scrofula, and syphilis— often induce a degree of anemia, even before any local manifestations of the constitutional disposition are discoverable. In syphilis, also, the dis
ease, after apparent recovery, is apt to leave behind it a state of profound anemia, which in many cases is to be attributed, not to the malady, but to the medication to which the patient has been subjected ; for a prolonged course of mercury is an unfailing cause of impoverishment of the blood. In rickets, the beginning of the disease is announced, and its progress accompanied, by a marked degree of anemia, which indicates the unfit ness of the blood in such a case to fulfil all the requirements of healthy nutrition. Of other special general diseases which may lead to diminution in the amount of haemoglobin and so set up anemia may be mentioned rheumatism, scurvy, and the cachectic condition induced by malaria.
Disease of special organs concerned in sanguification—the spleen, the lymphatic system, etc.—is, of course, followed by great alteration in the quality of the blood. In extensive amyloid degeneration of these organs, the marked pallor of the patient is one of the most striking symptoms of the disease ; and in lymphadenoma the patient is peculiarly pale and bloodless.
The causes which increase the consumption of the blood are : Profuse hemorrhages, as iu melena neonatorum, hemophilia and hemorrhagic purpura ; severe diarrhea ; chronic purulent discharges, as in cases of chronic empyema with a fistulous opening in the chest-wall; cirrhosis of lung with dilatation of bronchi ; albuminuria ; onanism ; etc. In this class, too, must be included rapid growth, which is a very frequent source of languor and anemia. It must be remembered, however, that at the age when growth is apt to be most rapid the child is often exposed to other influences which may also tend to set up impoverishment of the blood, such as confinement to close rooms and want of exercise.
Idiopathic anemia (which is sometimes seen in young people) may re sult from bad and insufficient food or other depressing cause acting upon the general system ; sometimes it is the consequence of mental shock, as in the case of a boy who was under the care of Sir William Gull, in Guy's Hospital. The lad began to suffer shortly after being attacked by a num ber of sheep in a field.