This course is an introductory exploration of the stuff of modern biology - the practices and objects that biologists have used to produce knowledge of living nature in the nineteenth and twentieth centuries. The course will look at how familiar concepts (e.g. the cell, evolution, the gene) were shaped by scientific workers' adoption of different methods and materials. This approach will allow us to situate biological inquiries within wider political and cultural contexts, while also drawing our attention to the way instruments mediated perceptions in the recording of observations and the execution of experiments. We will trace continuities and changes in the kinds of questions that naturalists and biologists posed, survey spaces in which they pursued their work, and become acquainted with a variety of humans, nonhuman organisms, chemicals, and machines assembled in these spaces. These exercises will familiarize us with diverse forms of labor in and beyond laboratories that have contributed to how humans understood the living world.