The globalization of sera evaluation between 1895 and 1925

Abstract During the development of an anti-diphtheria serum in the 1890s in France and Germany, the problem arose of how to evaluate the potency of an unstable substance of biological origin. This was solved by developing a complex, relational procedure, centred around standard toxin and sera, with guinea pigs and mice as bioindicators. After the marketing of anti-diphtheria serum in the German Empire in 1894, its production and sale were regulated by the state. The Royal Prussian Institute for Serum Research and Serum Survey soon became the global authority for the control and evaluation of biologicals; that is, substances of organic origin. This study analyses how serum evaluation transformed an unstable biological into an ‘objective’ remedy with a calculable therapeutic efficacy as measured in rodents.