[Universal history of mortality].
The history of human disease has to be based almost entirely on what we know about the changes in mortality and life expectancy; illness and suffering do not lend themselves to hard statistics, whereas births and deaths can be counted. To learn about the way diseases have been conquered in the past we have, therefore, to look at mortality. From this study we see that the major lethal diseases were conquered not so much by discovering how to treat them as by prevention. The decline on mortality began at the start of the past century, at a time of revolution and reform, and was greatly accelerated when the causes of many diseases were discovered at the end of the nineteenth century. Even in the twentieth century, the greatest improvements are still being achieved by preventive measurements.