With mother's milk, in the colon a buffer system round pH 5 is dominating which consists of short chain organic acids and the corresponding anions. Thus, the activity of the microbial metabolism is retarded. The degradation of lactose remains maintained down to the faeces. With cow's milk, a neutral buffer system on the basis of phosphate, bicarbonate, and protein degradation products causes a rapid lactose degradation already in the upper colon. Putrefactive metabolites thereby released and absorbed burden the infant's still immature detoxifying capacity.

Maltitol is found to be enzymatically hydrolyzed by the small intestinal mucosa of man, rat, and rabbit and metabolized by everted sacs of rabbit intestine at a moderate rate. On in vivo perfusion of maltitol (15.3 µmol/min) through the small intestine, 19% of the sugar alcohol is digested by gnotobiotic rats. 120 min after stomach intubation of gnotobiotic rats, only 31% of the ingested maltitol is found in the ileum. A daily application of 35 g maltitol to 4 human beings does not influence the parameters of well-being, compatibility and fecal state. It is concluded that maltitol will be digested and utilized by man, rat, and rabbit.

Analyses of the feces-flora and the feces-pH of breastfed infants and of infants nourished with commercial formulae (Ki-Na, Milasan) performed since 20 years were evaluated. In both regimens decreasing numbers of Bifidobacteria could be remarked. The dominating position of this groups of bacteria was limited more and more. Since 1971 the Bifidobacterium biotype, characteristic of feces of breastfed infants could be proved no more. Simultaneously germs of the E. coli-group and neonmycine-resistent forms increased. With breast-milk Proteus distinctly increased in the feces, whereas, formulae on cow's milk basis caused the reversed effect. Bacteroides and the group of H2S producing bacteria remained unaltered. In the stools of breastfed infants the pH-value increased slowly. These tendencies were marked still stronger in prematures. Enhancing influences from the environment as possible reasons for these developments were discussed.

Lactose and protein absorption from breast milk and a cow's milk preparation enriched up to 7% of lactose were studied in two infants with an artificial anus applied in the ascending colon region. The concentrations of protein, lactose, glucose and galactose were measured in the fistula stools. In addition, the stools were analysed microbiologically. There were relatively high concentrations of lactose and its decomposition products and low concentrations of protein and aminonitrogen in the fistula stools when breast milk was fed. When the cow's milk formula was applied, only traces of lactose but high amounts of protein were measured. The microbiological findings are in agreement with the hypothesis that the bacterial flora of the large intestine is influenced by the lactose and protein concentrations in the intestinal content which reach the large intestine.

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