Proper treatment of any condition depends on a knowledge of its causes. The process of finding out the cause of a condition is called diagnosis. Most conditions have not only immediate causes but also contributing causes. A man may have a broken arm from getting hit by a motorcar; perhaps he was blind in one eye and would not have been hit by the car had he been able to see it. A person gets tuberculosis when invaded by the germ of tuberculosis if his body is such as to be unable to overcome the germ. His body may have been weakened by under nutrition and exposure to cold and damp. Moreover, his germs may have come in overwhelming numbers from a boarder who had the disease, and who lived closely crowded with the family and did not know how to dispose properly of his sputum.
One of the first steps in making a diagnosis of a disease is to get a record of the patient’s life and environment related to his trouble. This the doctors call a “history.” Some remote fact in the patient’s past may carry the chief responsibility for his condition. If a prospective mother has German measles during the first three months of pregnancy, the child when born may be damaged in the eyes, the hearing or the heart.
A difficult childbirth may be responsible for cerebral palsy in the child. A man may get ulcers in the nose from inhaling chromium substances at his work. A woman may have a swollen eye because she touched it with a finger contaminated by some substance to which she is especially sensitive. A baby may have eczema because of sensitivity to milk. An executive may have high blood pressure because he is constantly at war with his employees and the board of directors. These are contributing causes with direct manifestations in body disturbances. Sometimes, however, the causes are remote. The mind seems to play a part in affecting the part of the body that may succumb to disease.