THE practice of medicine still depends on an element of clinical sense that is part of what, for lack of a better term, we call the art of medicine; each addition of precise objective observation to our armamentarium further hones the edge of our diagnostic abilities. In patients with sputum production as part of a disease, one can glean information pertinent to the abnormality through the intelligent examination of this material. The presence of sputum always implies some abnormal process of the bronchopulmonary system, and the cellular and noncellular components reflect the pathologic process. Certain technics are commonly used, and . . .