Gould's hopeful monsters were the homeotic mutants of Drosophila melanogaster, notorious for their transformed body parts—wing to haltere, antenna to leg. Although the essay lacks the trademark baseball reference, it follows his typical talky style. An anecdote comparing homeotics to sideshow freaks opens the essay. Next comes the 'I couldn't have said it better' zinger: "Congenitally malformed bodies are nature's experiments, uncontrolled by intentional human art to be sure, but sources of insight nonetheless." Historical tidbits follow, introducing organisms mythical and otherwise with mismatched body parts, then a second nod to scientific thinking—it's not enough to observe nature; one must look experimentally for explanations and mechanisms.
Much of "Hopeful Monsters" deals with "a series of remarkable experiments" in the lab of Thomas Kaufman, at Indiana University, where noted geneticist Herman J. Muller once worked. Kaufman wasn't the only one spending every waking hour examining flies with legs on their heads. ...
