EXPERIMENTS WITH WHITE RATS 



61 



CHART 25 



Graphs indicating average percentages of B. bul- 

 garicus and B. acidophilus appearing in the 

 different portions of the intestine of rats 

 fed on a diet containing lac- 

 tose and B. bulgaricus 



too 

 so 



eo 

 70 

 60 



50 

 40 

 JO 

 20 



/o 



D,-ef 



1 qmr. 



Bread lo. 



Beef J. 



Locrose I. 



B- acic/otJii/as I 

 3- bvlooricos u 



— H-" — tt^ H-" H- 



Parts of alimentary canal 



i 



s 



s 



05 



In the following experiments larger amounts of B. bulgaricus sus- 

 pensions were employed than heretofore, namely two to five cubic centi- 

 meters. When these amounts were administered to rats daily without 

 any accompanying carbohydrates no change whatever could be ob- 

 served in the character of the intestinal flora, and B. bulgaricus failed 

 to appear in the feces. 



Nine rats which had been on the basal diet for seven days were divided 

 into three groups of three each. One of these groups received two cubic 

 centimeters of the standard suspension of B. bulgaricus ; another five 

 cubic centimeters of the same material, while the remaining three rats 

 were given two cubic centimeters of the living suspension together with 

 two grams of lactose. The results were similar to those obtained in the 

 preceding experiments. The fecal flora of the first two groups of rats 

 remained apparently unchanged. The ingestion of even five cubic centi- 

 meters of B. bulgaricus suspension exercised no transforming influence 



