For as long as there have been means to distribute information widely, there has been the potential for information to go viral. These days, we have easily measurable indexes of virality—pageviews, tweets, shares, and likes, to name a few, but scholars are discovering other ways to quantify virality for the pre-internet era. The Infectious Texts project at Northeastern University aims to foster a clearer understanding of the circulation of ideas in the 19th century by looking at the viral spread of newspaper and magazine texts.