Catherine Wilson

The doctrine of preformation, which dominated the theory of generation for most of the 18th century, asserted a single divine act of creation for all plant and animal life. The original ancestor of each species, it was believed, held within its body the entire series of its type, each future organism enclosed inside its parent, waiting to be stimulated into growth at the moment of conception. ‘Ovists’ held that the pre-existing germ resided in the female egg, while ‘spermists’ (Pinto-Correia’s neologism for ‘animalculists’) located it in the ‘spermatic animalcule’ discovered in 1677 by Leeuwenhoek; the dispute between them is the subject of Clara Pinto-Correia’s book.‘