In her new book Gulp, the acclaimed science writer Mary Roach goes where few have gone before and few have ever desired to go: the human digestive system. Indeed, Roach marvels at the fact that this is her almost exclusive domain. And that's a good thing, because Roach is a gifted writer who is able to tackle a subject that often makes our stomach turn, and she does so in a way that is both humorous and informative.

It is in that same spirit that we asked Roach, in the video below, to take us on a tour through the alimentary canal to explain our biology from the perspective of bacteria. 

Watch the video here:

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