Medical journals: In 1665 the Royal Society in England published one of the first 2 scientific journals in the world: the "Philosophical Transactions of the Royal Society." The other was the "Journal des Scavants" (Scholars) which appeared in France the same year. From these 2 journals are descended the many thousands of scientific periodicals today, including all those devoted to the biomedical sciences and medicine, whether they be in print or newer media such as on CD or the Internet.
The original purpose of scientific and medical journals was to permit scientists and physicians to communicate with one another. A newer aim is to permit scientists and physicians to communicate with people who may not be trained as scientists or physicians -- to communicate with the world at large.