ORIGINS OF MODERNITY

natural philosophy

Leeuwenhoek, Antoni van (1632-1723)
Epistolae ad societatem regiam anglicam
Lugduni Batavorum : apud Joh. Arnold. Langerak, 1719.

Antoni von Leeuwenhoek was the leading microscopist of the early modern period, not simply because of the superior quality of his microscopes, but also because of the significance and quantity of his observations. He discovered sperm in 1677 and soon joined the debate over the nature of animal generation. While most were following William Harvey in seeing a central role for the female egg, Leeuwenhoek claimed that 'it is exclusively the male semen that forms the foetus'. He also held a preformationist theory, namely that the form of the adult animal is in the sperm. This is nicely illustrated in his diagram here.