196 STUDIES ім PLANT REGENERATION 
its original condition is the rule and not the exception, cases are 
known where the regeneration takes place at some distance from 
the wound, and at an angle to it, and yet the validity of the forma- 
tion as a true regeneration is undoubted.* Та any case where 
one or more organs are formed as a result of injury or loss, 
directly at the cut or at a distance from it, they should reasonably 
be considered as regenerated structures. 
On the other hand, the word regeneration ought to be limited 
to those cases in which an organ is formed, de novo, at a place or 
under conditions in which it would not normally be found. It is 
in this respect that it seems best to draw the line between regen- 
eration and ordinary growth and reproduction. Such an under- 
standing of the process would exclude phenomena like the growth 
of latent root and shoot rudiments of cut willow twigs (which 
Vochting, Morgan and Klebs place under the head of regeneration), 
the development of the shoot-meristems on separated leaves of 
Bryophyllum (which Goebel includes here), and the growth of the 
cotyledonary buds of the bean described by McCallum.f It is 
undoubtedly true, as each of these writers points out, that grada- 
tions between the two types of organ-formation exist, and that the 
conditions which bring about the development of a preformed bud 
may be very similar to those Which occasion the generation of a new 
one. ]t has, furthermore, been proved that such development 
or formation may be caused without wounding. Nevertheless, 
it seems logical that, for an accurate understanding of the circum- 
stances controlling organogeny, only such objects should be 
chosen for investigation as show at the beginning of the experi- 
ment no trace of the structure in question. 
In the following experiments, therefore, an attempt has been 
made to obtain some further information as to the behavior of 
Such budless pieces, As it is not always easy to determine 
positively whether or not primordia are present, there may be cases 
in the ensuing discussion where the distinction has been uninten- 
tionally overlooked ; and there certainly are one or two instances 
where, for the sake of securing evidence on other points, the ques- 
tion as to the absence or presence of such buds has been purposely 
* Morgan,T. H. Regeneration, 31. 
T McCallum, W. B. Regeneration in Plants. Bot, Gaz. 40: 97. 1005. 
