Various carbohydrates have been added to the fluid cultures of different strains of spirochetes in order to determine the behavior of the latter toward the carbohydrates. In the present experiment, amygdalin, arabinose, beerwort, dextrin, galactose, glycogen, glucose, inulin, lactose, levulose, maltose, mannite, raffinose, saccharose, and starch were tested with seven strains of Treponema pallidum and one strain each of Treponema calligyrum, Treponema microdentium, Treponema mucosum, and Spirochata refringens. The results may be summarized as follows: 1. In the media containing glycogen and glucose, Treponema microdentium did not grow as vigorously as in other sugar media, and an earlier degeneration set in. One strain of the pallidum and the calligyrum and mucosum showed a poor growth in the glycogen medium. Similarly, there was little growth in the second transfer of these spirochetes in the glucose medium. The growth of the spirochetes in the media containing carbohydrates other than those Just mentioned was generally good, and no difference could be distinguished between these and the control cultures without any carbohydrate. The only phenomenon which might be interpreted as indicating a favorable influence of these media upon growth was the abundant growth of the mucosum, which showed uniform length, regular curves, and active motility somewhat better than in the sugar-free medium. 2. The height of acidity was found in the cultures containing glycogen and glucose in the microdentium, amounting to 0.1 N 4.8 cc. for 10 cc. of the fluid culture. In the other sugar media the acidity varied between 0.1 N 2 cc. and 0.1 N 3.2 cc. for the same amount. In the control cultures, the acidity fluctuated from 0.1 N 0.8 cc. to 0.1 N 2 cc. There was no visible alteration in the appearance of the media after the spirochetes had grown for 3 or 4 weeks. In the case of Treponema microdenlium, a slight opalescence developed in the glycogen and glucose media after several weeks' standing, but there was no precipitation or coagulation of the proteins of the culture media. 3. There was no unusual morphological change in the spirochetes grown in the media containing any of the carbohydrates employed. The only phenomena which should be mentioned are (a) the frequent presence of the terminal appendages (or projections) in the refringens, and in most of the pallidum strains, and (b) the appearance of minute, retractile spherical bodies along the side of the spirochetes in the microdenlium cultivated in the glucose or glycogen media. Judging from the earlier degeneration of the species in the above mentioned media, these peculiar bodies may be interpreted as indicating a phase of plasmoptysis associated with the unfavorable surroundings prior to degeneration. Experimental evidence was not found for considering these spherules as a resistant or spore form of the spirochete.