Table 1: H2 and CH4 production by rat fecal homogenates.

Gas production (ppm)a
H2CH4
1 hour24 hours1 hour24 hours

Without added lactose486 ± 220380 ± 415
With added lactose2,001 ± 70614,235 ± 17,004

One gram of freshly collected feces in the colon was incubated as described in Methods. Lactose (1.25 g% final concentration) was added where indicated. H2 and CH4 were determined as described previously [1]. The concentration of the gases is expressed as part per million. The results are the average of three experiments, mean ± SD, with six rats in each experiment.