34 TRANSFORMATION OF THE INTESTINAL FLORA 



These experiments indicate that B. acidophilus is able to establish 

 itself in the intestine of the white rat when administered per os without 

 any accompanying carbohydrates. In every instance where two cubic 

 centimeters of the suspension were given it became the predominating 

 form throughout the enteric tract, almost completely eliminating or 

 suppressing all of the other bacterial types. The results warrant the 

 assumption that this organism is capable of adapting itself to intestinal 

 conditions and that positive implantation can be brought about. 



As will be seen in the following pages, the administration of only 

 one cubic centimeter of the standard B. acidophilus suspension did not 

 suffice to maintain for more than six to eight days the characteristic 

 acidophilus flora established through combined B. acidophilus and lac- 

 tose feeding. From the experiments thus far conducted it appears as 

 if amounts of the suspension much smaller than two cubic centimeters 

 do not possess any marked transforming influence. 



B. ACIDOPHILUS AND CARBOHYDRATE FEEDING 



The purpose of this series of experiments was to determine the com- 

 bined influence of relatively small amounts of either lactose or dextrin 

 and suspensions of B. acidophilus which by themselves had very little or 

 no transforming influence on the intestinal flora. Accordingly, a num- 

 ber of white rats were put on the basal diet until the flora was found to 

 be of the usual mixed type, when they received the different test sub- 

 stances according to a plan involving eighteen individual rat experi- 

 ments. 



Three of the rats were given two grams of lactose daily along with 

 the bread and meat ; three received two grams of dextrin each ; three, one 

 gram of lactose; three, one gram of dextrin; three, one gram of lactose 

 and one cubic centimeter of B. acidophilus suspension, and three one 

 gram of dextrin and one cubic centimeter of the bacterial suspension. 



In all of the rats which were fed two grams of the lactose or dextrin 

 there was a marked simplification of the intestinal flora.* This was 

 demonstrated by the examinations of the fecal suspensions and of ma- 

 terials from the different levels of the enteric tract. In striking con- 

 trast to these findings, however, were the results obtained in the feeding 

 of one gram of each of these sugars. The small amount of lactose or 

 dextrin stimulated only a partial transformation, and B. acidophilus 

 at the best attained a maximum of only about 50 per cent of the total 

 bacterial population. There was no radical suppression of other types 

 of ordinary intestinal microorganisms, and gas formation in the Veillon 

 tubes, while considerably reduced, persisted throughout the experiment. 

 (See Tables 11 to 14, and Charts 15 to 18.) 



*The tables are omitted to conserve space. The results were essentially the same 

 as in Tables 3 to 6. 



