C. A. WATKINS ON YEAST AND OTHER FERMENTS. 165 



same process ; but if you will refer to my diagram, you will see 

 that starcli does not contain an additional proportion of carbon, as 

 compared with sugar, but that it requires two equivalents of H to 

 equal it ; and that were one or two equivalents of carbon to be 

 oxidized and abstracted, we should not have sugar as the result. 



It is a well-known fact that, in germination, the starch is con- 

 verted into sugar by the diastase, which is probably formed from 

 the azotised matters by the vital action of the embryo. The oxida- 

 tion of some of the carbon contained in the seed is more likely to 

 be due to the decomposition of the sugar and other matters by the 

 growth of the embryo, the cells of which appear to me to perform 

 chemical functions similar to some of the fungi, for at this period 

 of its growth it must be remembered the vegetable action is 

 reversed, that it is now living on organic compounds and evolving 

 C O 2 gas; whereas, when it has expanded its leaves to the light 

 and atmosphere, its food must be reduced to simpler forms before 

 it can assimilate it, and it will then construct organic compounds, 

 and decompose C O 2 gas, eliminating oxygen. 



Malt contains about -3-L- part of its weight of diastase, and as 

 one part of diastase will convert 2,000 parts of starch into sugar, 

 it evidently contains a much larger quantity than is necessary for 

 the conversion of the remaining starch in the grain. This is taken 

 advantage of in various ways by distillers, &c, for the purpose of 

 converting unmalted grain and starch from other sources into sugar. 



The action of diastase and other similar soluble ferments is sup- 

 posed to be instantaneous when the matters on which they act are 

 also made soluble. 



As an illustration of this, I will tell you what is done at one of 

 the large distilleries in the North. 



Starch and grain are ground into a fine powder, and put into a 

 mash tun capable of holding several hundred quarters, and heated 

 till the starch granules burst, and a thick paste is formed. When 

 at the proper temperature, an infusion of malt is run in and agitated, 

 and in about two minutes the whole of this stiff mass becomes per- 

 fectly fluid, the starch being at once converted into sugar by the 

 diastase in the infusion* 



In the instances of fermentation I have brought to your notice, 

 I have shewn only the chemical transformations of the matters 

 fermented, these changes resulting in the re- arrangement of the 

 atoms or the molecules of which those matters are built up, thereby 

 giving rise to entirely new structures. 



