Table 2. Values of bacteria density in stool as reported in several past articles.

Article		bac. #/g dry stool (x1011)	dry matter as % of stool	bac. #/g wet stool (x1011)	CV(%)
Author	Year
Houte & Gibbons	1966	-	-	3.2	53%
Moore & Holdeman	1974	5	22%	1.1	78%
Holdeman, Good & Moore	1976	4.1	31%	1.3	66%
Stephen & Cummings	1980	4	29%(1)	1.2	25%
Langendijk et al.	1995	-	-	2.7	26%
Franks et al.	1998	2.9	-	0.74(2)	39%
Simmering & Kleessen	1999	4.8	-	1.3(2)	44%
Tannock et al.	2000	-	-	0.95	40%
Harmsen, Raangs, He, Degener & Welling	2002	2.1	30%	0.62	38%
Zoetendal et al	2002	2.9	-	0.77(2)	24%
Zhong et al.	2004	1.5	23%	0.35	73%
Thiel & Blaut	2005	3.5	25%	0.87	53%
He et al.	2008	1.5	-	0.39(2)	43%
Uyeno, Sekiguchi & Kamagata	2008	-	-	0.44	34%
Mean		-	27% ± 2%	0.92 ± 19%	46%

Full references are provided in Table A in S1 Appendix. Mean bacteria number is calculated using the geometric mean to give robustness towards outlier values. Values quoted directly from the articles are written in bold, values derived by us are written in italic. Values reported with more than two significant digits are rounded to two significant digits as the uncertainty makes such overspecification nonsensible. ± standard error of the mean.

⁽¹⁾ Value for [21] derived from their Table 1.

⁽²⁾ From derivation, assuming the averaged dry matter fraction of 27%.

From the measurements collected in Table 2, we calculated the representative bacteria concentration in the colon by two methods, yielding very close values: the geometric mean is 0.92·10¹¹ (SEM 19%) bacteria per gram of wet stool, while the median of the values is 0.91·10¹¹ (SEM 19% by bootstrapping, see methods in S1 Appendix). The variation across the population, given by the average CV, is 46%.