Bacterial interactions.

Bacterial interactions are important both in the formation of polymicrobial abscesses and in the control of the balance of the natural human floras. Investigations of the mechanisms controlling normal flora might be based on gnotobiology, but most of the conclusions are at present obtained indirectly by observations of the flora composition. One example is the typical bifid flora observed during breast-feeding. We studied changes in this following the introduction of bottle-feeding.