To test the theory, he and his colleagues analyzed bacteria in fecal samples from lab mice kept in normal 12 - hour cycles of light and darkness. (sciencemag.org)
Don't forget to bring along a fresh fecal sample for testing! (petsmagazine.ca)
Patients can, for instance, collect fecal samples and mail them to a laboratory, which can detect blood in the specimens. (scientificamerican.com)