a group of frogs in a pond with frogspawn

In the excerpt below taken from “Beautiful Experiments: An Illustrated History of Experimental Science” (The University of Chicago Press, 2023), Philip Ball dives into the 17th and 18th century experiments that sought to figure out the answer to a fundamental question: What induces eggs to develop? From microscopic observations of spermatozoa to special little sperm-catching trousers for frogs, Ball reveals how we came to understand fertilization. 

It was always clear that for the reproduction of humans and other mammals, both the male and the female have a role. But what role, exactly? Aristotle proposed that both sexes contribute a kind of generative principle called “sperma,” which combine to produce the rational human soul in the growing fetus in a process he called “epigenesis.” 

Source link