120 



REGENERATION 



only 138 milligrams while the total weight of the six apical leaves 

 was 2.465 grams. In this case 1 gram of dry weight of leaves 

 produced only 56 milligrams of shoots. 



The third node in Fig. 95 (to the right) produced no shoots as 

 was to be expected, but the fourth node in Fig. 96 produced 

 shoots, the total dry weight of which was only 88 milligrams per 

 2 451 grams dry weight of leaves. One gram dry weight of leaves 

 produced only 36 milligrams dry weight of shoots. 



Fig. 96. — Half stem removed with exception of region near fourth node where 

 shoot is formed. Leaf at apex. Oct. 2 to 23, 1923. 



If we make allowance for the possibility that the ascending sap 

 from the stem furnished part of the material of these shoots, calcu- 

 lating this effect from the fact that 1 gram dry weight of stem 

 (without leaves) produced 20 milligrams dry weight of shoots, 

 the absolute figures given for the material furnished by the leaf 

 for shoot formation will be slightly diminished, but the relative 

 values will not be materially altered, and the chief result will 

 remain the same; namely, that the material furnished by an 



