This sterile starch was mixed with sterilised water in tubes plugged with sterile cotton-wool. Eight tubes were taken, as follows:—
1. Sterile starch and water.
2. Sterile starch and water inoculated pure culture.
3. Sterile starch and yeast-water inoculated pure culture.
4. Sterile starch and asparagin inoculated pure culture.
5. Yeast-water alone inoculated pure culture.
6. Dextrin[169] and yeast-water inoculated pure culture.
7. Soluble starch[170] and yeast-water inoculated pure culture.
8. Starch mucilage and yeast-water inoculated pure culture.
These were allowed to stand on the incubator at 33°–35°C., and examined for acid each day by the method described in the previous communication for starch testing. They all remained neutral, although the bacteria developed in all but No. 1. These experiments were repeated several times, with the same result in every case. They show that this ferment is unable to act on starch either in its insoluble or soluble condition, alone or in the presence of nitrogenous bodies.