This article examines the attempts to introduce dissections of small animals in Swedish primary schools and secondary girls’ schools during the early twentieth century. It demonstrates that the new teaching methods were a part of a further ambition to transform the pupil’s relationship to nature and how teachers taught the natural sciences. Knowledge of the human body was emphasised and produced in analogy with other species, leaving none of the body’s organs or basic functions outside the curriculum. One of the strongest voices in this process was the Swedish physician Karolina Widerström (1856–1948). Through hers—but also others—engagement in annual training courses in basic dissection techniques for female teachers and the production of wildly distributed illustrated dissection manuals, extensive effort was made to change the pupil’s understanding of nature in general as well as their own bodies including the fundamental principles of human reproduction.