THE COMMON BACTEEIAL INFECTIONS 

 OF THE DIGESTIVE TEACT 



GENERAL CONSIDERATIONS RELATIVE TO THE 

 BACTERIAL FLORA OF THE HUMAN DIGEST- 

 IVE TRACT IN HEALTH 



IF one examines with the microscope the contents of 

 any portion of the large intestine of a human being or 

 of any mammal, the richness of the material in micro- 

 organisms is strikingly apparent, especially in stained 

 preparations. Their number has been estimated at 

 one hundred and twenty-six billions for the daily human 

 excreta. It is true that if the material is selected from 

 the lowest portion of the gut, many of the microorgan- 

 isms of a cultivable nature can be shown by suitable 

 cultural methods to be no longer living, but rather to 

 be undergoing a process of disintegration, partly owing 

 to a solution in their own juices a process of autoly- 

 sis. But even the dead and dying bacterial inhabitants 

 of the lower intestinal tract point to the multiplicity 

 of bacterial life at higher levels. 1 And not only are these 



1 Strasburger, J., " Untersuchungen tiber die Bakterienmenge 

 in menschlichen Faces/' Zeitschr. f. klin. Med., xlvi, p. 413, 1902. 



It has been estimated that the proportion of dead bacteria in 

 normal human fseces is often as high as ninety-nine per cent. It 



B 1 



