To avoid misinterpretations one should substitute the ambiguous notion of 'new disease' with 'emerging disease'. A disease can be classified emergent in at least five dif férent historical situations; 1) it existed before it could be first identified but was overlooked from a médical point of view because it could not be conceptualized as a nosological entity; 2) it existed but was not noticed until a quantitative and/or qualitative change in its mani festations; 3) it did not exist in a (...) particular région of the world before its introduction from other régions; 4) it never existed in a human population but only in an animal population; 5) it is completely new - the triggering germ and/or necessary environmental conditions did not exist prior to the first clinical manifestations. A sériés of historical examples illustrate this classification. (shrink)

The specific field of the history of science is the study and explanation of the origin and transformation of the structures of scientific knowledge. The historian of science should render understandable the reality of scientific research. The relationships between the history of science and the philosophy of science are examined stating that (1) the philosophical theories on the development of science have a scientific content only as much as they may be compared with the results of the history of science, (...) and (2) the philosophy of science does not refer to an immediate historical reality but to an intellectual reconstruction of the past. (shrink)