This was the subject of a recent communication to the Académie des Sciences, by M. Abelous. In the fluid obtained by frequent lavages of his own stomach (empty) he has isolated 16 species of microbes, the morphological characters and action of which on alimentary substances, he has studied. The 16 species comprise 7 known microörganisms: the sarcina ventriculi, the bacillus pyocyanous, the bacterium lactis aërogenes, the bacillus subtilis, bacillus mycoïdes, bacillus amylobacter, and the vibrio rugula. Of the 9 species that have not been described, I was a coccus, and 8 were bacilli. All these microbes resist the action of artificial gastric juice for a time much exceeding the mean duration of stomach digestion, especially when the cultures were rich in spores. Each of these species of microbes has a more or less energetic action on certain alimentary substances: 10 attack albumen, 12 fibrin, 9 gluten, 10 cause the more