VOLUME LX : NUMBER 4 
Oe oO 
BOTANICAL (QAZETLE 
OCTOBER 1915 
RULES AND MECHANISM OF INHIBITION AND CORRE- 
LATION IN THE REGENERATION OF 
BRYOPHYLLUM CALYCINUM 
JACQUES LOEB 
(WITH FORTY-ONE FIGURES) 
I. Introduction 
In the phenomena of regeneration the problem of correlation 
appears, that is, the influence of the whole on the part. A part cut 
out from a whole organism may regenerate, while no such regenera- 
tion will occur so long as the part is not separated from the whole. 
What are the forces inherent in the whole which exercise the con- 
trol over the part resulting in the prevention of regeneration ? 
We cannot form a definite idea of this inhibitory mechanism 
until we know the laws or rules underlying this prevention of 
regeneration or growth in the normal plant. Only if we succeed 
in finding such rules and if they are sufficiently simple can we with 
any hope of success begin to draw conclusions concerning the nature 
of the mechanism underlying these phenomena of inhibition and 
correlation. The reason why it is difficult to find such laws lies in 
the fact that the phenomena of regeneration in most organisms are 
too complicated or too indeterminate for such a purpose, and we 
are compelled to look for an organism which is especially favorable 
for such a purpose. The tropical plant Bryophyllum calycinum 
is apparently such an organism, and the writer has succeeded in 
ding some rules governing the phenomena of inhibition and 
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