CONDITIONS ESSENTIAL TO NUTRITION 101 



Other substances must be present in a plant, besides the Tstateh; 

 sugar, and gum, if these are to take part in the development of 

 tho germ, leaves, and first fibres of the radicle. There is no 

 doubt that a grain of wheat contains within itself the component 

 parts of the germ and of the fibres of the radicle. These compo- 

 nent parts are starch and gluten ; and it is evident that neither 

 of them alone, but that both simultaneously assist in the formation 

 of the root, for they both suffer changes under the action of air, 

 moisture, and a suitable temperature. The starch is converted 

 into sugar, and the gluten also assumes a new form, and both 

 acquire the capability of being dissolved in water, and of thus 

 being conveyed to every part of the plant. Both the starch and 

 the gluten are completely consumed in the formation of the first 

 part of the roots and leaves ; an excess of either could not be 

 used in the formation of leaves, or in any other way. 



The conversion of starch into sugar during the germination of 

 grain is ascribed to a vegetable principle called diastase, which 

 is generated during the act of commencing germination. But 

 this mode of transformation can also be effected by gluten, al- 

 though it requires a longer time. Seeds, which have germinated, 

 always contain much more diastase than is necessary for the conver- 

 sion of their starch into sugar, for five parts by weight of starch can 

 be converted into sugar by one weight of malted barley. This 

 excess of diastase can by no means be regarded as accidental, 

 for, like the starch, it aids in the formation of the first organs of 

 the young plant, and disappears with the sugar. 



Carbonic acid, water, and ammonia, are the food of fully-de- 

 veloped plants ; starch, sugar, and gum, serve, when accompanied 

 by an azotized substance, to sustain the embryo, until its first 

 organs of nutrition are unfolded. The nutrition of a foetus and 

 development of an egg proceed in a totally different manner from 

 that of an animal which is separated from its parent; the exclu- 

 sion of air does not endanger the life of the foetus, but would 

 certainly cause the death of the independent animal. In the 

 same manner, pure water is more advantageous to the growth of 

 a young plant than that containing carbonic acid, but after a 

 month the reverse is the case. (Saussuke.) 



The formation of sugar in the maple-trees does not take place 



