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March 26, 1904


JAMA. 1904;XLII(13):834-835. doi:10.1001/jama.1904.02490580024007

One is apt to become so deeply impressed with the fact that bacteria are producers of disease, that one may lose sight of the equally important fact that there are groups of bacteria which are useful to mankind and even essential to our well-being. The most important group in this large class of micro-organisms is that of the normal inhabitants of the intestinal tract. It is well known that the intestinal tract of most of the warm-blooded animals is literally swarming with bacteria of various kinds, but their importance to the host is often greatly underestimated. Indeed, it has been thought that the body would be better off without them, but this seems to be a mistake, as is made evident by the following facts pointed out by Strasburger.1 Experiments on birds and mammals indicate that the more highly organized animals can not live very long if all bacteria