JACQUES LOEB 95 



which diffuse into the blood and become available for the growth of 

 the regenerating tissues; in other words, it is the constant hydrolysis 

 going on in the organism which supplies the material for the growth 

 and regeneration of fasting animals. It remains for future investiga- 

 tions to find out whether the ratio between mass of growth material 

 circulating in the blood or lymph and the quantity of regeneration 

 obeys also the simple mass law established for regeneration in 

 Bryophyllum. 



For those interested in the dynamics of these processes attention may 

 be called to the fact that in our experiments the action of two masses 

 of active material, m and Wi, in twcj sister leaves is compared. 

 These masses are certain constituents of the two sister leaves, primarily 



. w 

 the chlorophyll, and their ratio — may be considered approximately 



constant throughout the duration of the experiment. Our experiments 

 have furnished the proof that the ratio of the mass of shoot regenera- 

 tion in two halves of a stem (each possessing a leaf at the base) is 



approximately proportional to — ; or in other words, that the law 



fyii 



controlling the quantity of shoot regeneration of the stem is a special 



case of the law of mass action. 



SUMMARY. 



1 . A method is given which allows us to measure the influence of the 

 mass of a leaf upon the quantity of shoots regenerated in an isolated 

 piece of stem. This method co^sists in isolating a piece of stem with 

 only two leaves left at the basal node and then splitting the stem length- 

 wise so that each half has one basal leaf. By leaving one leaf intact 

 while the size of the sister leaf is reduced, the influence of the mass of 

 the leaf upon the quantity of shoots regenerated by the stem can be 

 measured. 



2. This method has yielded the result that the mass of shoots regen- 

 erated at the apex of such a piece of stem increases under equal con- 

 ditions and in equal time with the mass of the leaf, and is approxi- 

 mately proportional to the mass of the leaf. 



3. Such an influence of the mass of the leaf upon the mass of shoots 

 produced by the stem is only intelligible on the assumption that the 



