Soured Milk: Its Nature, Preparation, and Uses

Abstract

THERE seems to be little doubt that as age advances the microbial flora of the human intestine, especially of the lower portion or large intestine, often undergoes a change both in the number and in the character of the micro-organisms present. From middle life onwards the number of microbes increases, and species capable of inducing putrefactive decomposition of proteins become more abundant. This change can be roughly gauged by making microscopical preparations of the dejecta and staining by the Gram process, a selective method by which certain organisms only are stained. In the child's dejecta Gram-staining microbes are relatively scanty and are mostly Bacillus bifidus and B. acidophilus, and it is noteworthy that these are lactic-acid producing bacilli. In and after middle life Gram-staining forms usually become more and more numerous, the Gram-staining species now being principally Bacillus putrificus and B. Welchii, bacteria which induce marked putrefactive decomposition of proteins.₁ In unhealthy conditions of the intestinal tract somewhat similar changes or various abnormal fermentations may occur.