Fertile substrate: the rise, fall, and succession of popular microscopy in Great Britain.

This paper examines the rise and fall of the British popular microscopy movement during the decades surrounding the turn of the twentieth century. It highlights that what is currently understood as microscopy was actually two inter-related but distinct communities and argues that the recognized collapse of microscopical societies in the closing decades of the nineteenth century was the result of amateur specialization. It finds the roots of popular microscopy in the Working Men's College movement and highlights how microscopy adopted its Christian Socialist pedagogy of equality and fraternity, resulting in a radical scientific movement that both prized and encouraged publication by its amateur adherents, who often occupied the middle and working classes. It studies the taxonomic boundaries of this popular microscopy, particularly focusing on its relationship with the study of cryptogams or 'lower plants'. It explores how its success combined with its radical approach to publication and self-sufficiency created the conditions for its collapse, as devotees established a range of successor communities that had tighter taxonomic bounds. Finally, it shows how the philosophy and practices of popular microscopy continued in these successor communities, focusing on the British expression of mycology, the study of fungi.