The knowledge of certain social codes is one of the factors that allows relationships between scholars to be born, to be established, to last, and to fade away. This is achieved through correspondence as well as through social interaction. Using the example of the network of Reaumurian naturalists in the 1740s, the article examines some episodes related to the problems of scientific priorities. It shows how knowledge of social codes influenced the fate of scientific discoveries and careers through the networks of which the scientists were more or less good users.