8 7 
Tropistic Movements of Plants. 
Dilute acids or alkalies in suitable concentrations gave the same effect. 
But I could never obtain the anti-ferment reaction without applying trop- 
istic stimulation. 
Experiments with roots mechanically hindered in growth by gypsum 
also tally with the before-mentioned experiments. To work with roots 
fixed with gypsum, the seedlings ( Faba major) were pinned into long and 
narrow wooden troughs filled with soft gypsum. They stayed in the solid 
gypsum for twenty-four hours in a vertical position, in damp air. And 
then, in those cases where geotropic stimulation was to be applied, they 
were placed horizontally for one hour. After being geotropically stimu- 
lated, the roots were freed from gypsum, their tips were cut off and the 
tests arranged. For such experiments the roots of Vicia Faba major were 
used, not being so easily injured as the roots of Lupinus : twenty-five Faba 
roots served for a series. The result of such an experiment is given ; the 
numbers have the same significance as above. 
Roots growing in sawdust : Roots in gypsum : 
unstimulated. 
stimulated. 
unstimulated. stimulated. 
2-7 
2-7 
2*7 2-7CC. “AgNO s 
2*2 
2*4 
2-3 2*4 „ „ 
i*7 
21 
i-9 2,1 „ „ 
1-2 
i-8 
i*4 !*8 „ » 
0.7 
i-5 
°'9 I *5 » 5> 
The anti-ferment reaction is therefore caused only by geotropic stimulus, 
even in this case. 
The following experiments show that a wound cannot by itself produce 
the anti-ferment reaction. The roots were wounded by the amputation of 
i mm. from the tip. 
Normal. 
Decapitated and placed 
Decapitated and placed for thirty minutes 
in vertical position. 
in horizontal position. 
2-0 
2-0 
2-0 CC. AgN0 3 
1-6 
i*6 
I *8 )} 55 
1*2 
1-2 
1*6 5, 55 
0.7 
0.7 
1*3 55 55 
o-o 
0-0 
0 * 7 5 5 55 
Neither can extreme degrees of temperature or light produce the 
anti-ferment reaction without a tropistic stimulus ; and the sum of my 
experiences is to prove that tropistic stimulation exclusively is able to 
cause the alterations of metabolism described by me in root-tips, stems, 
cotyledons, &c. 
I must therefore still differ from the view expressed by Noll (10) in 
the Botanische Zeitung, that the quantitative alterations of metabolism 
