214 THE POPULAR SCIENCE MONTHLY. 



sign of life. But wlien the seed is moistened and warmed, the starch 

 is changed to dextrin by the action of diastase, and the dextrin is 

 further converted into sugar. The food of the germ thus gradually 

 rendered soluble penetrates its tissues ; it is thereby fed and grows, 

 unfolds its first leaf upward, throws downward its first rootlet, still 

 feeding on the converted starch until it has developed the organs by 

 which it can feed on the carbonic acid of the air and the soluble min- 

 erals of the soil. But for the original insolubility of the starch it 

 would be washed away into the soil, and wasted ere the germ could 

 absorb it. The maltster, by artificial heat and moisture, hastens this 

 formation of dextrin and sugar ; then by a roasting heat kills the baby 

 plant just as it is breaking through the seed-sheath. Blue-ribbon 

 orators miss a point in failing to notice this. It would be quite in 

 their line to denounce with scathing eloquence such heartless infan- 

 ticide. 



Diastase may be obtained by simply grinding freshly germinated 

 barley or malt, moistening it with half its weight of warm water, al- 

 lowing it to stand, and then pressing out the liquid. One part of dias- 

 tase is sufficient to convert two thousand parts of starch into dextrin, 

 and from dextrin to sugar, if the action is continued. The most fa- 

 vorable temperature for this is from 140° to 150° Fahr. The action 

 ceases if the temperature be raised to the boiling-point. 



The starch which we take so abundantly as food appears to have 

 no more food-value to us than to the vegetable germ until the conver- 

 sion into dextrin or sugar is effected. From what I have already 

 stated concerning the action of heat upon starch, it is evident that 

 this conversion is more or less effected in some processes of cookery. 

 In the baking of bread an incipient conversion probably occurs 

 throughout the loaf, while in the crust it is carried so far as to com- 

 pletely change most of the starch into dextrin, and some into sugar. 

 Those of us who can remember our bread-and-milk may not have for- 

 gotten the gummy character of the crust when soaked. This may be 

 felt by simply moistening a piece of crust in hot water and rubbing 

 it between the fingers. A certain degree of sweetness may also be 

 detected, though disguised by the bitterness of the caramel, which is 

 also there. 



The final conversion of starch-food into dextrin and sugar is ef- 

 fected in the course of digestion, especially, as already stated, in the 

 first stage — that of insalivation. Saliva contains a kind of diastase, 

 which has received the name of salivary diastase and mucin. It does 

 not appear to be exactly the same substance as vegetable diastase, 

 though its action is similar. It is most abundantly secreted by her- 

 bivorous animals, especially by ruminating animals. Its comparative 

 deficiency in carnivorous animals is shown by the fact that, if vege- 

 table matter is mixed with their food, starch passes through them un- 

 altered. 



