This article examines the impact of the reporting practice and paper technologies like forms on reports that were later used for national morbidity statistics by studying the Swiss reporting system for infectious diseases between 1886 and 1921. Analysing the production processes of notifications shows the difficulties and solutions in the implementation of the statutory reporting process. Two disease outbreaks—a smallpox outbreak in Schaffhausen and a typhoid outbreak in the canton of Lucerne—serve as case studies. It is shown that reports are (...) not only objective representations of diseases, but also symbolize the medico-social interactions that produce them, timed by administrative tools like reporting forms and the act of reporting. This destabilises historical statistics and illustrates the complexity of the historical source material, as these interactions and their impact on reporting must be considered. These findings are further supported by examining the Swiss reporting system during the Spanish flu of 1918 and its failure to record influenza cases. (shrink)