In the annals of 20th-century biological research, few fields have captured the imagination and the funding of post-war science quite like gnotobiology—the study of organisms in a germ-free (GF) environment. By 1973, the Space Age was in full swing, and fears of terrestrial contamination, coupled with dreams of sterile lunar habitats, had propelled germ-free research out of niche biological labs and into the corridors of government agencies like NASA, the NIH, and the Max Planck Institute.

For the lay reader, the link between bacteria and waking up at 4 AM seems absurd. But by 1973, pioneering work by Dr. Rosalind McCabe (fictionalized here for representation) had proposed three mechanisms: