The aim of this paper is to discuss a key question in the history and philosophy of medicine, namely how scholars should treat the practices and experimental hypotheses of modern life science laboratories. The paper seeks to introduce some prominent historiographical methods and theoretical approaches associated with biomedical research. Although medical scientists need no convincing that experimentation has a significant function in their laboratory work, historians, philosophers, and sociologists long neglected its importance when examining changes in medical theories or progress (...) in scientific knowledge. The reason appears to have been the academic influence of the then dominant tradition in the history of ideas, but was also due to a misconception of what could usefully be termed the view on “historical ontology.” During the last two decades, there have been many books and research articles that have turned towards the subject, so that the study of experimental practice has become a major trend in the contemporary history and philosophy of medicine. A closer look at the issue of laboratory research shows that concepts in medicine and the life sciences cannot be understood as historically constant, free-standing ideas, but have to be regarded as dependent on local research settings. They often carry particular “social memories” with them and thus acquire important ethical implications. (shrink)