In 1870s Switzerland colloid goiter was a common ailment, usually marked by a huge glandular swelling on the front of the neck. In later years it would be understood that a simple iodine supplement to the diet could significantly reduce the disorder. But in the nineteenth century, surgical removal of the thyroid gland was the only known cure. However, in the absence of effective anesthetics and antisepsis, surgical attempts to remove a goiter meant almost certain death for the patient. This was the challenge faced by Swiss surgeon Theodor Kocher, who devoted his medical career to making thyroidectomy, or the removal of a thyroid gland, a relatively safe procedure by applying new notions of antisepsis. Kocher performed thousands of thyroidectomies in his career, and the post-operative research and data he collected helped amass new knowledge about the physiology of the thyroid gland and its related disorders. For his...