Abstract
Discrete maladies or illnesses tend to produce particular signs and symptoms. This natural correlation makes possible the process of diagnosis and prognosis. In fact, so strong is our belief in the regularity of signs and symptoms that the process has long been regarded as straightforward, if not easy: “. . . there is nothing remarkable,” Hippocrates suggested some 2,400 years ago, “in being right in the great majority of cases in the same district, provided the physician knows the signs and can draw the correct conclusions from them”.1