102 BOTANICAL GAZETTE [avout 
do not exist; for if the stem of the bean be severed from the root 
system and kept moist, new roots appear along the stem. Similarly, 
when many roots and leaves or other parts are cut away, new shoot 
primordia are organized from cortical or other tissues, and it seems 
quite probable that the same stimulus which starts the development — 
of many latent primordia will in many cases where they are absent — 
incite their origin from already differentiated tissues. 
What now are the possible factors operating in these cases? 
The various theories and possibilities suggested fall naturally into — 
a few general classes: (1) wound stimulus; (2) disturbance in nutri 
tive relations; (3) changes in water content; (4) accumulation a 
certain places of definite formative substances; (5) correlation; (6) 
relative age and degree of maturity of the different parts of a membet; 
and (7) growth tensions. Each of these will be discussed in connectio 
with the experiments relating to them. 
Unless otherwise stated, the plant used was Phaseolus, and it 
every experiment a sufficient number of plants were used to insure 
reliability of the result, and check experiments were always carefully ) 
arranged. Where there was any diversity in the result the exper 
ment was always repeated. Of the total number of experiment 
only the more striking ones will be described, and for convenient 
in the discussion these will be numbered in the order in which thé 
are presented. | 
DISTURBANCE IN NUTRITION. 
When a growing part is removed, a large part of the food : 
would have been used by it may now be unused in the plant, and 
may be accessible to other parts. If during the spring the tip 
shoot of almost any tree be removed, some of the buds which 
otherwise lie dormant until the next year develop into shoots 
6 and 7). Here, and in Onoclea where GOEBEL (2) secu 
metamorphosis of sporophylls into foliage leaves by the con 
removal of the former, KLEBS (5) sees an essential factor 7° 
disturbance occurring in the nutritive conditions. In the axils of 
cotyledons of Juglans regia there are a number of buds which 
GOEBEL (4, p. 209) has pointed out, do not develop unless the z= 
minal bud be removed. This arrest of these buds is due GOBBEP 
says “to all the available food material being devoted to the deve 
