INFECTIONS OF THE DIGESTIVE TRACT 21 



radical changes in the character of the food the colon 

 bacilli have in many instances been observed to resume 

 their prominent position in the intestinal contents. It 

 is reasonable to believe that the return of more normal 

 secretory conditions in the digestive tract is a very 

 influential factor in determining the reinstatement of 

 the legitimate flora. If this be true, the therapeutic 

 value of introducing colon bacilli into the intestine 

 (with food or by high colon injection) with a view to 

 utilizing their restraining action upon injurious races 

 must be less than would at first sight appear to be the 

 case. There is need for much careful research in regard 

 to this question. 



Influence of Reaction on the Growth and Products of 

 Intestinal Anaerobes. If mixed faecal flora be grown 

 in sugar bouillon and in sugar bouillon containing 

 calcium carbonate for one week at 37 C., it will be found 

 that a considerable amount of volatile fatty acids has 

 been formed in each case. The quantity will usually 

 be found to be greater, often considerably greater, in the 

 flask containing calcium carbonate than in the flask with- 

 out it. Similar results are obtained if one substitutes 

 magnesium carbonate for the calcium salt. The observed 

 difference in the quantity of acids is therefore probably 

 not due to a specific effect of the calcium salt, but to its 

 action in maintaining a neutral reaction. 



In a series of observations of the sort just mentioned, 

 which were carried out by Dr. A. J. Wakeman, two things 

 are worthy of note. First, it was found that in nearly 

 all instances the molecular weights of the volatile fatty 



