INFECTIONS OF THE DIGESTIVE TRACT 49 



health. Escherich, one of the few students of this sub- 

 ject, found that the number of intestinal bacteria in- 

 creases gradually from above downward in the small 

 intestine, undergoing a sudden and extreme increase at 

 the level of the caecum. Even as high as the duodenal 

 level moderate numbers of microorganisms could be 

 found corresponding to the types of the B. coli and B. 

 lactis aerogenes groups. Schmidt, making use of Weigert's 

 method for staining fibrin, noticed that a preponderance 

 of Gram-positive over Gram-negative forms does not 

 begin until the level of the colon is reached. From the 

 middle of the colon downward, the characteristic Gram- 

 positive fa3cal flora begins to dominate the picture and 

 appears exclusively present in the rectum a striking 

 evidence of the fundamental difference between the flora 

 of the upper and lower portions of the intestine. 



I have had an opportunity to make microscopical 

 examinations (using Gram's method of staining) of the 

 contents of the digestive tract of nursling infants dying 

 within the first six months from conditions not closely 

 connected with the digestive tract (e.g. acute broncho- 

 pneumonia). On comparing the results of these exami- 

 nations with those obtained by Moro by the use of the 

 Escherich-Weigert fibrin stain, they were found to be so 

 nearly alike in their leading features as to make it 

 probable that the following description, based on these 

 two sets of observations, is generally applicable to the 

 case of healthy nursling children. 



In normal nurslings the mouth contains few bacteria, 

 and such as it contains are for the most part organisms 



