JACQUES LOEB 



83 



and their axillary buds are at right angles to each other. If we, there- 

 fore, split a stem longitudinally into two halves (Fig. 1) in such a way 

 that the plane of section is at right angles to the Hne connecting the 

 two most apical buds (1, Fig. 1), the section cuts through the buds in 

 the next node (2, Fig. 1), and injures them more or less, while it leaves 

 the buds of the second next (3, Fig. 1) node intact, and so on. It 

 happens for reasons which need not be discussed here that in such a 

 stem as a rule only the most apical bud (1 , Fig. 1) grows out. 



Fig. 1. Diagram showing the method of splitting the stem longitudinally 

 in order to investigate the influence of mass of basal leaf upon shoot production. 

 1,2,3, designate the three pairs of dormant buds, two in each of the three nodes of 

 the stem. 



The following method was used for testing whether or not the 

 quantity of regeneration in a piece of stem is controlled by the simple 

 mass law which holds for the regeneration of shoots in the stem. 

 From the stem of Bryophyllum were cut pieces containing three nodes 

 (Fig. l). All the leaves were removed except the two at the basal 

 node. Then the stem was split lengthwise so that each half of the 

 stem contained one basal leaf and one intact bud at the apex (1, Fig. 1), 

 while the two buds (2, Fig. 1), in the middle node were generally 

 injured in the operation. As stated, in most cases only the apical 

 bud grows out in such a piece of stem. By leaving the leaf in one of 



