EXPERIMENTS WITH WHITE RATS 



59 



CHART 29 



Graphs indicating average percentages of B. hul- 

 garicus and B. acidophilus appearing in dif- 

 ferent parts of the intestine of rats 

 fed on a diet containing lactose 

 and B. bulgaricus 



Die-f- 



-H- 



-If 



-tt- 





Parts of alimentary canal 





g 



e 



05 

 a 



executing the tests for reducing substances two cubic centimeters of the 

 filtrate were added to five cubic centimeters of Benedict's solution, the 

 mixture boiled for one minute, and allowed to remain in the refrigerator 

 for ten to twelte hours before taking the final readings.* The bac- 

 teriological tests were carried out in the usual manner. 



The feces and the fecal material from the caecum and colon of the 

 lactose- and dextrin-fed rats gave positive reduction tests with the 

 Benedict solution, and revealed a completely transformed flora domi- 

 nated almost entirely by B. acidopMlus. On the other hand, the 

 samples from the rats which received maltose, sucrose or glucose gave 

 the same results as those of the control animals which received the basal 



* In the testing for lactose heating with dilute acid was resorted to for inversion 

 of the sugar. 



