The article explores the early decades of the nineteenth century as an era of what we call embryonic modernity. It focuses on Finland which, in 1809, became a Grand Duchy of the Russian empire. The article concentrates on early mass phenomena as embryos of an emerging modern culture. We scrutinize our subject through three different lenses, starting with social infectivity on a minor scale, the unrest caused by students. We then investigate the contagiousness of ideas seen through the press as a news medium in the 1820s. The last section concentrates on the news about cholera and its rapid spread during the early 1830s. We argue that historical embryos were formations of social relationality, composed of affects, beliefs, expectations and sentiments. These formations of emotive dynamics had the capacity to be imitated; they became components of larger social entities by extending their contagiousness to new regions and populations.