Edit 2021 experiment illustration to reflect the final experiment

[mikemc]

Should consider any ways in which the current illustration may give a misleading representation of the procedure we ultimately used. One aspect in which the illustration is misleading is in how the mock+feces sample type is portrayed. It is shown as starting from a tube with a mock pellet and a fecal pellet in a tube prior to homogenization. However, in reality it was necessary to spin down and resuspend the germ-free fecal pellet prior to adding it to the mock pellet, so the two were never in a tube together in such a discrete unsuspended form as shown here. However, this illustration where the mock and fecal pellets are shown distinctly is a convenient clear representation of the three sample types, and may be worth keeping for this reason, with an appropriate caveat given in the caption or Methods. I could replace the tube in the third panel ("Create dilution series...") with a fecal-only tube to avoid the suggestion that the germ-free and mock pellets remained distinct before homogenization.

[mikemc]

When editing, also add subfigure labels A, B, and C to refer to in the Methods text.