From Spontaneous Generation to the Limits of Life: The Microscopical Experimentalist Research from the 1760s to 1800

Parallel to the birth of systematics, an experimental trend developed for new microscopical objects, and new research subjects emerged during the 1770s, such as the ambiguity of microscopical species (whether certain algae are animals or vegetables), green matter, ‘reviviscent’ animalcules (rotifers, tardigrades), or criteria that would distinguish animal from vegetable on a microscopic scale. Historians also established that spontaneism was not dead, although various methods of generation had been described.¹ All these issues enlarged the communities of users of the microscope and provided the experimental basis for nineteenth-century work.² The manifold problems encountered led researchers to establish instrumental, methodological and communication rules for microscopical observation. Yet the relationship between research and communication betrays the presence of a major crisis in microscopical research between the 1770s and the 1800s.