In the 1800s, a German doctor named Wolff made significant discoveries regarding human bone structure. By examining X-rays of infants as they progressed from crawling to walking, he understood that bones undergo evolution to accommodate the demands of weight-bearing activities. This led to the principle that the shape of bones is influenced by their function, summarized in Wolff's insight that "form follows function," as explained by Lang in Mary Roach's book, "Packing for Mars."

However, while Wolff's work was groundbreaking, he did not foresee the potential negative effects of excessive X-ray exposure. The primitive technology of the time posed risks, particularly related to cancer, which contrasts sharply with the advancements we have today in medical imaging. Roach's exploration reveals how our understanding of science and medical practices continues to evolve, often learning from past missteps.