168 -Dr, Colqukoun*s Essay [Sept. 



decomposition. eiitire!y5Mig'(?//m5. It was accordingly denomi- 

 nated Panun/y and held to consist in the simultaneous decompo* 

 sition and mutual re-action of all the constituents of flour. 

 Subsequently to that period, the action of the fermentation has 

 been held not to take place at once upon all the constituents of 

 flour; but has been limited at one time to the glutinous ingre- 

 dient, as by the Messrs. Aikin, in their excellent Dictionary of 

 Chemistry,''^ and at another to the starch ; but of late, the pre- 

 vailing opinion has been that the only principal subject of its 

 action is the saccharine constituent. It is the latter theory 

 which is to be maintained in this Essay ; the fermentation in 

 dough, so far as it is useful to the baker, being ascribed solely 

 to the resolution of the saccharine principle of the flour into 

 carbonic acid and alcohol, in consequence of its being brought 

 into a situation predisposing it to pass into the vinous fermenta- 

 tion. Undoubtedly, if the saccharine fermentation be suffered 

 to exhaust itself in any dough, it will be found that a new 

 fei'mentation, of a different kind, will succeed it ; but it is this 

 latter decomposition alone which is conceived to be injurious to 

 the bread, while the former is the source of all the benefits 

 which the best fermentation is found to confer. It appears, 

 therefore, that the first material point to be determined, in the 

 chemical history of the bread-fermentation, is, whether the 

 saccharine principle be truly the exclusive subject of its 

 operation. 



In order to illustrate this fundamental point, let it be first of 

 all considered what are the only other constituents of wheaten 

 flour besides the saccharine principle. These may be correctly 

 enough stated to be starch and gluten ; for the albuminous and 

 gupfimy principles, both from their small amount and from other 

 circumstances to be hereafter adverted to, seem to be of little 

 ipfluence on this question. Let the well-known phsenomena of 

 decomposition, as occurring in each of these two bodies taken 

 separately, be attended to. They will be found to differ very 

 decidedly from those which take place in the panary fermenta- 

 tion. And if the characteristics marking the decomposition of 

 the remaining ingredient of flour, the saccharine principle, be 

 compared with the acknowledged appearances and effects of 

 that fermentation which does take place in dough, their simila- 

 rity, or rather identity, would seem to leave little room for doubt 

 po the subject. 



; In the first place, with regard to starch and gluten. There is 

 no tendency to undergo any decomposition whatever induced in 

 starch, by merely exposing it for a few hours to the moderate 

 temperature used in the preparation of dough ; and even moist 

 gluten, in the short period necessary to commence and complete 



* Article, Bread. Publuhed in 1807. 



