ABSTRACT
It is virtually impossible to imagine the development of microbiology without the microscope, but the relationship between the instrument and the conceptual framework of modern microbiology is rather ambiguous. Seventeenth-century microscopists were certainly able to see a new world teeming with previously invisible entities, including protozoa, molds, yeasts, and bacteria. While Antoni van Leeuwenhoek was quite sure that he had discovered “little animals,” that were produced by parents like themselves, others took exception to this conclusion. Indeed, questions concerning the nature, origin, and activities of the citizens of the microbial world were not clarified until the late nineteenth century. Several accounts of infusoria were, however, published in the eighteenth century. For example, in 1718, Louis Joblot (1645-1723) published an illustrated treatise on the construction of microscopes that described the animalcules found in various infusions. Carl von Linnaeus (1707-1778), the great arbiter of the names, classification, and (almost) the existence of living things, was quite skeptical of microscopic studies. Believing that an orderly arrangement of all species was the supreme achievement of a naturalist, Linnaeus found the creatures discovered by Leeuwenhoek, Joblot, and others rather a nuisance. Such creatures were tossed into the all-purpose category known as Vermes, in a class called Chaos. Sorting out these minute, but apparently infinitely diversified creatures provided a special challenge for nineteenth-century microscopists.
