[Child mortality in francophone Europe: the state of the matter].

The interest of a comparative approach at a supranational level is to identify and to underscore the trends that sometimes overcome regional characteristics. Therefore among the great variety of parameters likely to influence mortality, the factors acting on levels and the factors acting on trends must be strictly distinguished. What is more striking where comparisons are possible, is the conformity of trends and the fact that evolution is not continuous but moves forward in stages. This is the reason why socio-economic explanations must be excluded. A whole part of Western Europe knew an important decline of infants' mortality at the turn of the XIXth and XXth centuries and probably also of the XVIIIth century. It was such a rapid, simultaneous extensive decline that the interference of very general factors must be acknowledged. Then the question is raised of the effect that a modification in the pathological balance can produce on the chances of infants to survive. The hypothesis considered here is a minor incidence of infectious diseases connected to changing bio-meteorological conditions (a drop in the temperature gap between winter and summer) which would have acted as a transforming mass along with cumulatiave effects because of the interactive synergy between ill-nourishment and infections. The evolution in the XIXth century and the contrasted profiles or mortality according to age confirm the hypothesis of a modification in the nosological context unrelated to the economic conditions.