Next to pain, _Cough_ is the symptom, especially in the colder months of the year, that we have most to deal with. The question _How long?_ is vastly the most important one about cough. One can also measure its _severity_ by the question, "Does it keep you awake?" and to some extent by the question, "Does it prevent work?" More important is the question, "Is it dry or productive of sputum?" The patient's description of his sputa in gross, without any microscopic examination, is also of a good deal of use. There are usually three things a patient can tell us about it: either it is yellow, or it is white, or it is bloody. There are two other important questions about bloody sputa. Unless one gets these answered, the mere fact of spitting blood is not important. We must know whether there are merely streaks of blood which one often sees in the sputa of anybody who coughs hard, are of no importance, and have nothing to do with tuberculosis. But if, in contrast with this, we can really establish evidence of the spitting of blood in quantity, we have almost proved a diagnosis of tuberculosis. In ninety-nine cases out of one hundred the spitting of blood in quantity means tuberculosis. "In quantity" means a cupful or thereabouts of pure blood. If the doctor does not find tuberculosis after that he should nevertheless assume it, for it is almost always there. I should pay no attention to negative physical finding in such a case. The next point to ask about is whether the patient's _breathing_ is _wheezy_. When a horse has become broken-winded we can hear his breathing in the street as he comes along. He has become emphysematous. We find this wheezing respiration in emphysema, asthma, and bronchitis, which are diseases important for us to distinguish from tuberculosis; we almost never get it in tuberculosis. If the patient complains of _dyspnea_--difficult, rapid breathing, "short breath" as we say--we shall ask about _oedema_ or swelling of any part, especially of the legs. In every patient who has a cough we are concerned primarily with the diagnosis of one disease, that is, tuberculosis, its presence or absence. Hence every patient who coughs should be questioned about the other symptoms of tuberculosis and especially about _emaciation_. A man with a chronic bronchitis or emphysema does not lose much flesh; he does not become emaciated. A person does not become thin from throat trouble. Hence emaciation, especially recent, is a helpful guide to the doctor in making up his mind. _Fever_ we investigate for the same reason. The only disease that often causes cough and fever during a long period is tuberculosis. Unfortunately the patient's statement about fever is usually unreliable. We can believe most of what he says on the rest of these points. But he does not know whether he has fever or not.