After presenting some general considerations relative to the bacterial flora of the human digestive tract in health, and showing that none of the experimental studies made by investigators is really conclusive as to the necessity of bacterial action in the digestive tract for the maintenance of health in adult mammals of the highest type, Dr. Herter proceeded:
Clearly, then, the intestinal bacteria are not required to carry on the ordinary digestive processes of normal nutrition. It has been supposed that the intestinal bacteria aid in the digestion of cellulose which they are undoubtedly able to decompose fermentatively. This argument loses much of its force if it be true, as lately maintained by Bergmann, that most of the cellulose eaten by herbivora is provided with intracellular enzymes capable of decomposing cellulose.
The real significance of the normal intestinal flora probably lies, not in any immediate relation to processes of digestion but