Before proceeding to discuss the immediate subject of this communication, it may be well to recapitulate shortly the views on the general question of the meaning of strength of flours which I expressed in the last number of this journal. It may perhaps be remembered that I suggested that strength, as defined by Humphries and Biffen, to be the capacity of making large well-piled loaves, must be a complex of at least two factors. One of these factors, that which regulates the size of the loaf, I showed to be the power of continuing to evolve carbon dioxide gas throughout the later stages of dough fermentation. I described how to measure this property by incubating in a bottle at 40ºC. a mixture of 20 gms. flour, 20 c.c. water, and ½gm. yeast, the bottle being connected to a gas measuring apparatus, and the volume of gas given off being read from time to time. A number of experimental figures were given, which showed that the size of the loaf which a flour could make, was directly connected with the rate at which it gave off gas in the later stages of dough fermentation, at the time when it was ready for the oven.