Recent decades have seen extensive changes in how researchers in the sciences work. Online platforms enabled by Web 2.0 technologies (collectively known as “open” or “networked” science) have created multiple new channels for informal communications, revolutionizing the ways in which scientists collaborate and share results. Meanwhile, digitization and open access publishing have brought fundamental change to modes of publication and distribution for scientific journals. Yet the primary vehicle for the formal publication of results, the scientific article, has been much slower to alter in format. This paper will examine the functions that peer-reviewed journals have served within the scientific community since the founding of the Philosophical Transactions of the Royal Society of London, and the reasons for the remarkable stability and persistence over time of the journal system. It will also chart the development of the rhetoric of scientific discourse from its early author-centered approach to later object- and method-centered formats, leading to the highly structured research articles of the twentieth century. The evidence suggests that informal communication has been quick to adapt to the networked environment of contemporary research and is growing in importance for working scientists. The journal article, meanwhile, remains the format of choice for purposes of the professional record, much as books were when journals first appeared.