Personal Investigations

Summary The investigation has shown that in a series of 46 healthy breast‐fed infants between the ages of 10 days and 5 months the bifidum count varied between 1 100 million and 153 000 million per gramme, the mean value being 32 000 million. Ninety per cent of the values exceeded 10 000 million per gramme. Some of the children underwent a series of two to five tests over a period of up to 5—7 weeks. Some of them showed a continuously low and others a continuously high bifidum count, and others again very great variations without presenting any clinical symptoms of disease. Further, the number of Bact. bifidum was not demonstrably correlated either to that of other bacteria or to the age. The number of other bacteria varied between <1 million and 6 000 million per gramme faeces, with a mean value of 160 million for bacteria growing on dextrose agar. In 65 per cent of the cases the pH was between 5.0 and 6.0, with variations in both directions. In the main the faeces had an acid odour.