86 



REGENERATION OF BRYOPHYLLUM CALYCINUM 



reproduction of the same experiment (with left and right sides 

 reversed) . 



These experiments prove that equal masses of leaves at the base of a 

 piece of stem cause the production oj approximately equal masses of 

 shoots at the apex oJ the stem in equal times and under equal conditions. 



Fig. 2. Drawn after nature. The upper specimen with whole leaf and 

 the one beneath it with reduced leaf are always the two halves of the same piece 

 of stem split lengthwise in the way indicated in Fig. 1 . The shoots at the apex 

 of the stem with whole leaves (upper row) are considerably larger than the corre- 

 sponding shoots with the sister leaf reduced in size (lower row). As a matter of 

 fact, the masses of regenerated shoots were in proportion to the masses of the 

 leaves attached to the base of the stems. The reader will also notice that the 

 stems with whole leaves (upper row) have formed roots at their base, while those 

 with reduced leaves have not yet formed any roots (though they did so later). 

 It is also noticeable that the shoots with whole leaves show geotropic curvature, 

 while those with reduced leaves are still straight. 



Even where some of the leaves were wilted the mass of shoots produced 

 at the apex was always greater when the mass of leaves was greater, 

 but it was no longer possible to prove approximate proportionality 

 though such proportionality in all probability existed. 



In the experiments presented in Table II the stems as well as the 

 leaves were suspended in moist air to eliminate the influence of ab- 



