By Tyler Nix, Kathryn Funk, Jeffrey S. Reznick, and Erin Zellers

A wealth of medical history awaits your exploration in the National Library of Medicine’s (NLM) free and full-text digital archive of journals PubMed Central (PMC)! Known to most of its users as a free, full-text archive of recent biomedical journals, PMC also reaches back in time over two centuries.

These articles represent just a fraction of the more than one million articles comprising PMC’s historical holdings, scanned from 160 journal titles beginning in 1809 and spanning 200 years. These holdings are the outcome of the Medical Journal Backfiles Digitization Project (2004-2010), a partnership between the Wellcome Trust, the Joint Information Systems Committee (JISC), NLM, and a number of medical journal publishers interested in publishing backfiles online. Building on this previous effort, the NLM and the Wellcome Trust are now working together to expand PMC’s historical holdings in the area of mental health and general medicine, a collaboration that will add substantially to the current total PMC archive of over 3.8 million articles.

PMC is full of amazing individual items, but what follows is a wider view of what its one million historical articles look like. The word clouds below reveal the depth and diversity of this historical collection by journal title, its major subject areas by NLM Medical Subject Headings, and its chronological scope by publication year, stretching from the early nineteenth century to the late-twentieth century.

see: http://circulatingnow.nlm.nih.gov/2016/02/23/pubmed-central-visualizing-a-historical-treasure-trove/