656 



QUANTITATIVE LAWS IN REGENERATION. II 



Stem. It also illustrates the principle that when in one part of the 

 leaf growth is very rapid the growth in other parts of the leaf is retarded 

 or inhibited for the reason that the flow of material is towards the 

 rapidly growing organs. 



These drawings were made later than those given in a previous 

 paper,^ which were for this reason less striking. 



The inhibitory effect of a small piece of stem on a leaf does not 

 last permanently. It is possible that at first the piece of stem grows 

 in the way described thus inhibiting growth in the leaf, but that later 



Fig. 3. The same as Fig. 2. 



the rate of growth in the piece of stem diminishes, and parallel with 

 this the inhibition of the piece of stem on the growth of roots and 

 shoots in the leaf diminishes also. 



Loeb, J., /. Gen. Physiol., 1919-20, ii, 373. 



