94 
Frederic Czapek . — The Anti-ferment Reaction in 
The same, cutting off 1*5 mm. : — 
Unstimulated . . 2-0 
i-6 
1-2 
n 
— o-4 cc. — 
10 
AgNO, 
Stimulated . . . 2-0 
1.7 
i *4 
— °-6 „ 
>> 
The same, amputating % 
mm. : — 
Unstimulated . . 2*0 
i-6 
i* 1 
n 
— o-4 cc. — 
10 
AgNO, 
Stimulated ... 2-0 
i-6 
1/2 
— 0.5 „ 
55 
It was shown by a preliminary experiment that decapitation is not 
able to produce the anti-ferment reaction to any degree without geotropic 
stimulation. 
Neither wounded nor stimulated 
2-0 1-6 
— o-6 
0-2 CC. 
A AgNO, 
Decapitated, not stimulated . . 
2*0 1*6 
— o-6 
0-3 „ 
55 
Decapitated and stimulated . . 
2-0 1-7 
— o-9 
o-6 „ 
55 
The parts cut off were immediately ground and added to the other 
parts of the root-tips used for the test. 
I may mention that the anti-ferment reaction can be investigated in 
isolated root-tips of 5 mm. length placed horizontally. 
These experiments show that the anti-ferment reaction is to be 
obtained in spite of removing the tissues of root-tip up to the motor 
zone, and that at least 1-5 mm. of the root-tip must be removed to 
hinder the anti-ferment reaction. This is in complete agreement with my 
previous experiments, and contradicts the statolith hypothesis in a manner 
which demands an explanation. Nemec ( 24 ) recently expressed the view 
that possibly cells containing statolith starch could still exist in a length 
of nearly i-o mm. of the root-tips. But according to my experience, in 
roots of Lupinus decapitated to i-o mm. there are never any statolith cells, 
nor can there be any regeneration of such cells in the period of stimulation, 
viz. half an hour. 
Therefore other possibilities must be examined. Thus it is not 
impossible that the starch-cells of the root-cap are to be considered as 
being the chief organs for perception of the geotropic stimulus, but that 
the displacement of bodies contained in other cells may be available for 
the statolith function, though in a less effective manner. There is even the 
possibility that such displacements produce anti-ferment reaction, but no 
complete or normal curvature. That there exist processes connected with 
the anti-ferment reaction, but never producing any visible curvature, can 
be shown by the phenomena of roots laterally illuminated, as mentioned 
in the sequel. Unfortunately, in the case of geotropism this is difficult 
to decide, because the stimulus of wounding has itself an influence, and 
the failure of curvature may just as well be due to the effect of wounding 
as to the non-perception of the geotropic stimulus. 
