298 



QUANTITATIVE LAWS IN REGENERATION. I 



Five pairs of sister leaves were suspended sidewise, the lower edge 

 dipping in water, and roots and shoots formed at the lower edges 

 only. Table I gives the dry weights of the leaves, of the shoots, 

 and of the roots at the end of the experiment. The figure in paren- 

 theses, behind the dry weight of the shoots, expresses the number of 

 shoots formed. The first horizontal row gives the dry weights of 

 these organs for one set of five leaves (Set I), the second horizontal 

 row gives the dry weights of these organs for the five sister leaves 

 (Set II). The third horizontal row gives the ratio of the dry weights 

 of the two sets of organs. The masses of the two sets of sister leaves 

 were almost aHke, and the ratio of the two masses was 1.02. Ac- 

 cording to the law expressed in the writer's former pubHcations the 



TABLE I. 



Duration of Experiment 34 Days. 



mass of shoots and of roots produced by the two sets of leaves should 

 also be alike (within the Kmits of accuracy of these experiments). 

 The ratio of the two masses of shoots and roots should, therefore, 

 have been approximately 1.00. 



The figures of the third row show that the ratio of the dry weights 

 of the two sets of shoots is exactly 1.00 and the ratio of the two sets 

 of roots is 0.94. The two sets of sister leaves having equal mass produced, 

 during the same time and under equal conditions of temperature, mois- 

 ture, and illumination, equal masses of shoots and of roots. 



In the next experiment one set of six isolated leaves (Set II) 

 remained intact while the mass of each leaf of the second set was 

 reduced to approximately one-half by cutting away one side of each 

 leaf (Set I) (Fig. 1). The masses of the two sets of leaves were 



