Dr Colquhoun on the Art of baking Bread. 75 



mentation. And it has been ascertained by M. Vogel, that 

 in baked bread there exists pretty nearly the same quantity of 

 gluten as in common wheaten-flour, and that of the starch, 

 three-fourths remains entire ; while the other fourth is only 

 converted into a gummy matter, similar in appearance and 

 properties to torrefied starch, a change which could have no 

 effect in infusing a gaseous body into the bread. It seems, 

 therefore, to be a point scarcely admitting of additional proof, 

 that it is neither the starch nor the gluten which is concerned 

 in the ordinary fermentative process which takes place in 

 dough ." 



The mucilaginous and albuminous principles of wheat-flour 

 exist in such small proportion that they cannot be supposed 

 capable of causing fermentation. The only remaining con- 

 stituent, therefore, is the saccharine matter, a principle con- 

 tained in wheat-flour to the amount of five per cent., and 

 which, from its strong tendency to ferment, will readily account 

 for the phenomena. In confirmation of this view, Dr C. 

 made the following experiments. " After suffering the fer- 

 mentative process to exhaust itself in a mass of dough, and the 

 dough to be brought into that situation in which the addition 

 neither of yeast, nor starch, nor gluten, had produced any 

 effect on a similarly ex-fermented mass, I tried the renewal of 

 a little yeast to* the dough, along with a small addition of the 

 other constituent of the flour, the saccharine principle. On 

 adding common refined sugar in these circumstances to the 

 amount of four per cent., the process of fermentation immedi- 

 ately recommenced, and in its appearance, activity, and duration, 

 was just a repetition of the previously exhausted process of 

 fermentation. After a lapse of about the same period, it, in 

 the same manner, totally ceased" 



This experiment, taken in conjunction with the foregoing, 

 seems to leave no doubt that the saccharine principle is the 

 true and only cause of the fermentation. Dr C. mentions one 

 fact, however, which at first sight appears contradictory; 

 namely, that a loaf of well-baked bread contains nearly as 

 much saccharine matter as is contained in wheaten-flour pre- 

 viously to fermentation. Thus M. Vogel found 3.6 per cent 

 of sugar in good bread. Dr C. explains this circumstance in 



