458 QUANTITATIVE LAWS IN REGENERATION. III. 



Experiment V. October 11, 1921, to November 1, 1921. 



Dry weight of 



shoots per gram 



of stem. 



4 long apical stems with 6 nodes each. sm. mg. 



Dry weight of stems 3 . 921 



" "Sshoots 0.113 29.0 



" " " roots 0.0134 



Control. 4 basal pieces of 2 nodes each. 



Dry weight of stems 3.744 24.0 



" " 10 shoots 0.090 



Experiment VI. December 11, 1921, to January 17, 1922. 

 7 long apical stems with 6 nodes each. 



Dry weight of stems 6.634 



" " 12 shoots 0.340 51.0 



" " roots 0.0512 



Cotitrol. 7 short basal pieces of 2 nodes each. 



Dry weight of stems 3 . 560 



" "12shoots 0.1770 49.6 



" " roots 0.0128 



If we consider only those figures in the experiments where the small 

 control pieces of stem were situated basally from the long stem (the 

 pieces 4 and 5 in Figs. 6 and 7), we notice that the differences of 

 shoots produced per gram of dry weight of the controls differ never 

 more than 25 per cent from those produced by the large pieces of stem 

 and that in some cases the difference is only about 6 per cent. Con- 

 sidering the limitations in the experimental conditions — especially 

 the fact that part of the stem may not function normally, especially 

 the ends near the cut, or the fact that individual buds may have been 

 injured by parasites, etc. — the agreement of the figures seems 

 remarkable. 



These results leave no doubt that within the limits of accuracy of 

 these experiments the dry weight of the shoots produced at the apex 

 of a long piece of defoliated stem is about equal the mass of shoots the 

 same stem would have produced had the buds in all of its nodes 

 been able to develop. 



