While chlorosis, a term applied to a condition characterized by a diminished percentage of hemoglobin in the blood occurring in young girls, is becoming increasingly infrequent, in cities at least a lowered hemoglobin is now seen rather often in adults. In fact, in many conditions of impaired health and vitality, without any specific disease, the hemoglobin percentage is found to be between 70 and 80. Several causes, in cities, for this lowered hemoglobin may be hypothecated, from the inhalation of carbon monoxide in small quantities, more or less constantly, to a lowered percentage of hemoglobin associated with subacute or chronic focal infection. In all serious diseases, secondary anemia occurs sooner or later. Iron needed for the production of hemoglobin in health is acquired from the iron-containing food and drink. In disease conditions, chemical or glandular disturbances in the body seem to prevent this normal bodily acquirement of iron from nutriments.