CONVERSION OF STARCH INTO SUGAR. 213 



339. Although this deposition of starch fulfils a part so evi- 

 dently important in the vegetable economy, we cannot doubt the 

 wise and benevolent intention of the Creator, in thus providing 

 a store of nutritious and palatable food for Man, in situations in 

 which he can so easily obtain it ; and it is interesting to remark 

 that, from the completely separate form in which it exists, it 

 may be obtained in a state of purity from many vegetables, 

 which, as a whole, are of very poisonous character. An illus- 

 tration of this fact occurs in the Cassava, which forms a most 

 important article of food in almost all the warmer regions of the 

 globe. This substance is the starch contained in the root of a 

 plant termed Jatropha Manikot; and the root contains also a juice 

 so poisonous, that it is employed by some of the savages among 

 whom this plant abounds, to tip their arrows and spears. The 

 root is usually ground or rasped into a sort of coarse meal ; and 

 from this, when put under pressure, the juice runs off, leaving 

 the starch nearly pure. The Tapioca of Brazil is nearly the 

 same with Cassava. 



340. Starch cannot be applied to the nutrition of the tissues, 

 however, without undergoing an important change, which re- 

 duces it, in fact, to the condition of sugar or gum. Of this 

 change there are many instances in the progress of vegetation. 

 That which is best known, is the conversion of the starch of 

 seeds into sugar, which takes place during germination ; and 

 upon this the process of malting is founded. The grain of barley 

 contains a large quantity of starch ; but, when the embryo is 

 made to sprout, this starch is converted into sugar for its nou- 

 rishment. Now the germination of the seed is caused, by steep- 

 ing it in water, and then placing it in a warm atmosphere ; and 

 this is the first stage of the process of malting. As soon, how- 

 ever, as the growth of the embryo has proceeded far enough, for 

 the proper quantity of the starch to be converted into sugar 

 (which is known by the length of the young root, and by the 

 appearance of the grain itself), the germination is checked by 

 the application of a higher degree of heat, which kills the young 

 plant ; and the newly-formed sugar can then be employed, to 

 give sweetness to water or other fluids. In the same manner, 



