Feeding and Being Fed. Supply Cycles and Nutrition Regimes at the Royal Prussian Institute for Experimental Therapy, 1900 to 1910. The article explores the everyday life and especially the feeding practices in the laboratories of the Institute for Experimental Therapy and the Georg Speyer House in Frankfurt, Germany, in the decade after 1900. The text focuses on the experimental animals and their entangled relationship to humans in the two institutes where life‐scientists tested the therapeutic effect of chemicals and dyestuffs on (...) pathogens and tumors. For this purpose countless animal experiments were conducted in the fields of chemotherapy and cancer research. The article focuses on the importance of animal feeding and feeding practices in the experimental processes and serum testing procedures. The behaviour of the animals, their health status, their appetite and weight were constantly monitored and deemed fundamental to the outcome of the experiment. Animal feeding was therefore an important factor within the epistemological process of knowledge production. Animal feeding was both orientated towards the needs of the experiments and governed by economic needs. Within their economic (life) cycles, the ontological status of the animals changed: they became vectors of pathogens and information, economic resources, objects of exchange, living resources and life stock for ongoing experiments, patients, and sometimes even food for other animals. Overall, feeding experimental animals played an important role in the research process. (shrink)