I’m used to working in the controlled environment of a lab—we knew exactly what was in those tubes of fluid. But with the pigs, we were throwing the capsules into a black box. If the subject ate that morning, its stomach might be full of gastric fluid. If it didn’t, and it was lying on its back, the gut contents didn’t slosh around as usual, so parts of the stomach got dry. A few times, we deposited the sensors right in a dry patch. With no data to transmit, those experiments failed. Eventually, we hope to use this pill to better manage gut-related diseases in humans. So scaling up from a test tube to a 150-pound pig showed us how much can change in a live subject.