Perhaps I can make this clearer by contrast with its opposite. A person who has just developed a scarlatinal rash, who has just coughed and raised a considerable quantity of blood, who has just lost the power to move half of his body, who has just begun to have swelling of the face, naturally consults a doctor at once. If he then comes to a dispensary for treatment, he has come at a time which is the right time, the reasonable time, considering the nature of his malady. Something new has happened. An attack has been made which should be foiled if possible at once. The clue for usefulness on the part of the doctor is thus fairly clear. If, on the other hand, a person has had more or less back-ache all his life, and has grown used to getting along and doing his work, even enjoying life in spite of it, he may suddenly come to a dispensary for that back-ache because he has seen in the newspaper the wholly false statement that pain in the back means kidney trouble. Yet when he comes to the dispensary _he may say nothing whatever about his having seen this newspaper advertisement_. Indeed, it is very unlikely that he will mention this at all. He will describe his back-ache as something which demands immediate treatment, and the doctor may set in motion extensive and probably useless activities of investigation or treatment which never would have been undertaken had he known just what it was that brought the patient to the dispensary that day rather than months earlier or later. So far I have spoken only of cases in which the visitor's studies in the home make it clear that the case is not as bad or not as manageable as it might have seemed if one had known only what the patient himself could reveal in the dispensary. But occasionally on reaching the patient's home the visitor may find reason to believe that the symptoms are much more serious, the disease much more urgent, than could have been realized from the story told and the facts obtained at the dispensary. The visitor may find in the home conditions of disorganization, dirt, disorder, serious malnutrition, discouragement on the part of other members of the family, arguing a much more serious condition of the patient than one would have realized from talking with him at the dispensary. As a result of such findings the doctor, who must spend his energies for the patients who need him most, will see that he had better give more time and more effort to the patient than he would otherwise have thought right.