Intestinal Implantation of Bacillus acidophilus. 193 



The present investigation has shown, also, that the ingestion of 

 pure cultures or suspensions of B. acidophilus results in a similar 

 change. 



The administration of 2 grams of either lactose or dextrin to 

 white rats, in connection with a basal diet of bread and meat, 

 caused within three to six days a complete transformation of the 

 fecal flora from the ordinary mixed type to one strongly domi- 

 nated by B. acidophilus, while the same amounts of maltose, 

 sucrose and glucose failed to exert any transforming influence. 

 The ingestion of 1 gram of lactose or dextrin brought about a 

 partial change, whereas the addition of 1 c.c. (nephelometer 5) 

 of living cultures of B. acidophilus to the I gram of carbohydrate 

 effected a complete simplification of the intestinal flora. Iden- 

 tical results were obtained by the administration of 2 c.c. of the 

 B. acidophilus culture or suspension alone. Post-mortem exam- 

 inations of the different sections of the alimentary canal of rats 

 harboring a simplified flora of the aciduric type revealed a general 

 distribution of B. acidophilus throughout the length of the in- 

 testine. 



The implantation of B. bulgaricus was not effected by the 

 ingestion of even 5 c.c. of B. bulgaricus suspension of the same 

 concentration as those of B. acidophilus, either with or without 

 accompanying lactose. However, when B. bulgaricus and lactose 

 were given simultaneously a transformation of the intestinal 

 flora took place corresponding to that obtained with the feeding 

 of 2 grams of lactose alone. 



In feeding experiments with human subjects it has likewise 

 been shown that either lactose or dextrin, when added in sufficient 

 amounts to the ordinary diet, causes a pronounced transformation 

 of the intestinal flora within four to six days, with a marked 

 predominance of B. acidophilus. With a single exception thus 

 far, the ingestion of 300 grams of either of these carbohydrates 

 led to such a proliferation of B. acidophilus that it entirely domi- 

 nated the flora and effected an almost complete suppression of all 

 other viable bacterial types. The simple character of the flora 

 tended to remain permanent so long as the ingestion of these 

 carbohydrates was continued. The administration of 400 grams 

 was necessary in the one exception noted. 



