Abstract
The absence of a microbial flora produced a twofold increase in the absorption of d-xylose in germfree mice as determined by the everted sac technique. The existence of a similar increase was confirmed in germfree rats by using one in vitro and two in vivo techniques. Monocontamination of germfree mice with pure cultures of microorganisms also produced changes in xylose absorption. Studies on water, Na+, and K+ absorption in germfree mice indicated that the flora produced no significant change in the absorption of Na+ or in the movement of water and K+.