FIRST GROWTH OF A GRAIN OF WHEAT. 55 



germination is afterwards recovered almost entirely by 

 the young plant. 



The plant developed under these circumstances 

 barely increases in substance to any appreciable degree, 

 even though it may continue vegetating for weeks. 

 The organs developed from a grain of wheat weigh all 

 together, when dried, no more than the grain did before 

 germination. The relative proportion of the non-nitro- 

 genous and azotised substances in them is almost the 

 same as in the farinaceous body, the constituents of 

 which have in reality merely assumed other forms. 

 The leaves, roots, stem, leaf-buds and root-buds collect- 

 ively represent the constituent" parts of the seed, trans- 

 formed into organs and apparatus now endued with the 

 power of performing certain operations which serve to 

 carry on a chemical process, whereby external inorganic 

 substances, with the cooperation of sunlight, are con- 

 verted into products analogous in all their properties to 

 the materials from which these organs themselves arose. 



The organic process of cell-formation presupposes 

 the presence of the protoplasm, and is independent of 

 the chemical process by which the latter is generated ; 

 but this chemical process is indispensable to the con- 

 tinuance of the cell-formation. 



In a young plant which has been developed in pure 

 water alone, the chemical process must soon come to an 

 end for want of the necessary external conditions. The 

 leaves and roots in this case can do no work as formative 

 organs. In the absence of food they generate no products 

 upon which the continued existence of the plant de- 

 pends. When they have arrived at a certain state of 

 developement, the cell-formation ceases in themselves, 

 although it is still continued in the new root-buds and 

 leaf-buds. The latter stand to the movable contents of 

 the previously existing leaves and roots in the same re- 

 lation as the embryo of the w^eat-seed to the farina- 

 ceous body. The non-nitrogenous and azotised constit- 

 uents which represent the working capital of the exist- 

 ing roots and leaves are transformed as these die into 

 new organs, and new leaves are developed at the ex- 



