In the 1850s, the British were mad for microscopes. It was not the first time. Robert Hooke’s Micrographia, published in 1665, had been tremendously popular with readers, including Samuel Pepys, who once stayed up until two in the morning marvelling at the giant fleas and minuscule cells that the book revealed to him. The wealthy Pepys was in the unusual position of being able to afford a microscope of his own. In general, though, these devices remained out of reach for amateurs until the Victorian era, when enthusiasm for nonspecialist study of the natural world made microscopes, like stereoscopes, a regular feature in middle-class parlours. The unseen world first described in the seventeenth century could now be seen.

Agnes Catlow’s Drops of Water; Their Marvellous and Beautiful Inhabitants Displayed by The Microscope (1851), was published toward the beginning of miscroscopy’s second wave. Focusing on animalcules, or Infusoria (the “little animals” that infuse stagnant water, undetectable to the naked eye), Catlow acts as a friendly guide to any amateur in possession of a good microscope — an inexpensive instrument that not only provides entertainment “at all seasons of the year” but permits us to enter an ocular wonderland.

Indeed, Catlow in her preface seems to anticipate the tiny little door through which Alice, on the cusp of her adventures, longs to go:

My readers must fancy themselves spirits, capable of living in a medium different from our atmosphere, and so pass with me through a wonderful brazen tunnel, with crystal doors at the entrance. These doors are bright, circular and thick, of very peculiar construction, having taken much time and labour to bring to perfection. A spirit named Science opens them to all who seek her, and feel induced to enter her domains. At the end of the tunnel we find other portals, much smaller, and more carefully constructed, and two or three in number; when these are opened, we are in the new world spoken of. And now I see your astonishment; your minds are bewildered with the variety of new beings and forms you behold, all gliding and moving about without noise and at perfect ease.

Instead of the hookah-smoking Caterpillar and Cheshire Cat, however, the new beings in Catlow’s enchanted realm are varicoloured blobs with proboscises and “hairs in constant motion”. The accompanying lithographs, by A. Achilles, are captivating, but the real drama of the book lies in Catlow’s accounts of the animalcules, enlivened by a scientist’s precision and a storyteller’s knack for detail:

A great portion of the green matter found on stagnant water is formed by individuals of the genus Glenomorum; they cluster occasionally, and possess a single red eye, and a double hair-like proboscis.

The family Cryptomonadina is distinguished by the individuals having a lorica, or shell, which in some is found to be inexhaustible by fire.

Throughout Catlow is careful to emphasize the cheerful novelty of what can be seen in these “minute portions” of the Creator’s work. She calls herself an amateur and addresses herself to amateurs — most of whom she assumes to be children, new to science. Her intention is to keep things light. Yet, even acknowledging the beauty of her descriptions, there is more than a hint of the monstrous in the shifting, aqueous shapes of these invisible creatures.