"Why not?"
"If you let the dough stand in a temperature of between 90 and 120 degrees for a certain time, fermentation will take place, and it can then be baked."
"But why should it ferment?"
"Bread raising is merely fermentation. All flour is largely composed of starch. The high temperature, of 100 degrees or over, causes the starch to turn first into sugar, then into alcohol and carbonic acid, and the gases thus formed force their way up through the dough, causing it to swell, as you have often noticed."
Fig. 8. Imperfectly leavened. Perfectly Leavened. Samples of Bread
Without further instructions the boys began the making of bread. Shortly afterwards the Professor appeared laughing immoderately.