EXPERIMENTS WITH HUMAN SUBJECTS 79 



In the attempts to implant B. acidophilus in the absence of special 

 carbohydrates five subjects received 300 cubic centimeters each of the 

 whey broth cultures, in addition to their usual daily diets, for a period 

 of ten days. The bacterial culture was taken in one dose, usually 

 before the noon luncheon. 



Within two to four days after the first administration of the viable 

 living bacteria, B. acidophilus colonies were observed in both the whey 

 agar plates and in the Veillon tubes in appreciable numbers. The 

 Gram-stained slides gave additional evidence of the simplification of 

 the intestinal flora. Gram-positive rods resembling B. acidophilus con- 

 stituted 75 to 80 per cent of the total bacterial count. This trans- 

 formation reached its maximum on the fourth to sixth day, and the 

 simple flora persisted as long as the B. acidophilus cultures were ad- 

 ministered. (See Tables 38 to 42, and Chart 34.) B. acidophilus 

 dominated the fecal flora to practically the same extent as when 300 

 grams of lactose or dextrin were fed. (See Chart 34.) 



The conclusion may be drawn from the above experiments that B. 

 acidophilus is capable of establishing itself in the intestinal tract of 

 man when administered per os without accompanying special carbo- 

 hydrates. In each of the subjects it became the predominating organ- 

 ism in the enteric tract, almost wholly suppressing or eliminating all 

 of the other viable bacterial types. The results warrant the assumption 

 that the organism in question is able to accommodate itself to the 

 environmental conditions of the human intestine, and that positive 

 implantation can be eifected. This assumption has been strengthened 

 further by the results of subsequent experiments. 



SIMULTANEOUS USE OF THE SPECIAL CARBOHYDRATES 

 AND BACILLUS ACIDOPHILUS 



The purpose of these experiments was to determine whether half 

 or even less of the transforming doses of lactose and the whey broth 

 cultures of B. acidophilus can effect a marked simplification of the in- 

 testinal flora in man when these agents are administered together. 

 Accordingly, five human subjects whose flora was known to be of the 

 usual complex type were given, in addition to their regular daily diet, 

 150 grams of lactose and 150 cubic centimeters of the acidophilus 

 cultures. 



The results are summarized in Tables 43 to 47. They show a pro- 

 nounced change in the character of the intestinal flora, with a strong 

 predominance of B. acidophilus as the outstanding feature. A com- 

 parison of these results with those obtained with the subjects who had 

 received only 150 grams of lactose reveals striking differences. Fol- 

 lowing the combined feeding the development of B. acidophilus was so 

 pronounced that, barring one exception, within four to six days after 



