35^ 



LECTURE XXII. 



and those where they are made use of; so that with the progressive growth of the 

 shoot-axes and roots, the distance through parts already fully grown which the forma- 

 tive substances must traverse on their way to the parts which are growing and which 



I'IG. 239.— Diagram of a dicotyledonous plant. J young- embryo in the seed; // the same somewhat older ; 

 /// the plant after the conclusion of germination when commencing to assimilate independently. The black 

 portions indicate the growing points, containing chiefly proteid materials ; the grey ones are the parts which 

 are elongating, where the proteid matters are less abundant, but into which starch and sugar have passed to be 

 employed in growth. The parts left white are fully grown ; and c and b are carrying on the function of 



make use of them becomes greater and greater. Figure 239 may serve to 

 illustrate this, since it represents diagrammatically the distribution of the states of 

 growth of a young Dicotyledon. All the organs already fully developed, and 



