Darwin's famous phrase of the 'struggle for existence" is taken as a metaphor. Semantically it has its origins in everyday language but was given a specific meaning in the context of his theory. Subsequently, the metaphor was transferred back into everyday use but also had an impact on the historical and social sciences. Darwin's metaphor is one of the most famous cases of this type of metaphor transfer into the sciences and back. The analysis focuses on the German context where the phrase was translated into "Kampf um Dasein." The "Kampf" metaphor's role in various different contexts (discourses in the popular press) reveals the multifariousness of its usage. It reaches from the navy policy to colonialism and commerce and ultimately played a normative role in Nazi race hygiene policy.