[Changes within Lactobacillus and Bifidobacterium species]

Laboratory rats with a gut flora unambiguous free from Bifidobacterium revealed three days after an application of a lactose-rich food a dominating Lactobacillus plantarum flora. Up from this date, Bifidobacterium could be detected for the first time. At the beginning, there was to be observed merely B. adolescentis and B. pseudolongum, at the 5th to the 10th day B. bifidum supervened. Finally this species together with B. infantis was dominating. With in vitro experiments, by a systematic modifying of the medium changes from Bifidobacterium species typical to faeces from infants to such species only to meet in faeces from adults could be observed only after a long time of cultivation.