Soluble Ferments Digestion. 225 



starchy and saccharose matters can be accumulated in the cells of plants, 

 as it is in the roots of the beet and maple, and in the stem of sugar 

 cane and sorghum, &c. , and in seeds. At a certain period the ferment- 

 ing organism, zymase or diastase, becomes active and decomposes the 

 starch into assimilable constituents, which are then consumed in build- 

 ing up the tissues of the plant. 



CHAPTER XXVIII 



SOLUBLE FERMENTS DIGESTION. 



It was mentioned in the last chapter that the organized cells of yeast 

 and other forms of organic ferments are accompanied by another princi- 

 ple, which is called a zymase. This word simply means a ferment, and 

 is often used as a synonym of diastase. The yeast plant is called an 

 organic ferment, and an insoluble ferment, while the zymase is a soluble 

 ferment. 



The yeast plant evidently owes its ability to live on sugar to its asso- 

 ciation with this zymase. In fact, not only the yeast plant but every 

 other plant and animal requires the association and co-operation of a 

 zymase, or perhaps more than one, in order to have the materials 

 required for its growth and repair put in such shape that they can be 

 assimilated, just as it is essential that the brickmaker, the quarryman, 

 the sawmill man, &c., shall prepare materials for the bricklayer, the 

 stone cutter and the carpenter to work into the several parts of a build- 

 ing. 



The fermentations which take place in the animal body and which 

 result in the splitting up of the food into such shapes that the pieces 

 will fit the various tissues of the body, are spoken of under the general 

 term digestion. Some of the processes of digestion may be imitated by 

 the chemist in his laboratory. 



Thus the hydration of starch, by which it is resolved into glucose 

 and dextrine, and the further resolution of dextrine into maltose, all 

 which is accomplished by the digestive ferment in the natural state, may 

 also be performed by the chemist with dilute sulphuric acid. There is a 

 ferment in the body which turns the fats of the food into soap. The 

 soap maker does this, too, by boiling the fats with an alkali. 



The following is a general list of food-producing substances upon which the zymases 

 act in the ordinary processes of digestion. 



1. Proteids (or albuminoids). Containing Carbon, Hydrogen, Oxygen and Nitrogen, 

 and sometimes Sulphur and Phosphorus ; Gluten of flour, vegetable fibrin, Albumen of 

 the white of egg and blood serum; Fibnn of the blood; Syntonin, chief constituent 

 of muscle and flesh ; Casein, chief constituent of cheese ; Legumin, vegetable casein ; 

 Gelatin from connective tissue, and Chondrin from cartilage. 



