i 
ANDREWS AND ELLIS: REACTIONS OF HAIRS OF SALVINIA 445 
They continued to fade and by the fifteenth day all were entirely 
yellow. 
This experiment shows that the plant can obtain a certain 
quantity of its food from the decomposing organic matter offered 
to it in the way above described. The amount that can be taken 
up by the leaf hairs, however, is small and is insufficient to supply 
the demands of the plant. The Salvinia with organic matter on 
its leaves seemed to have an advantage but this advantage in 
nature is only occasional or as chance offers. 
“Experiment 6. Pieces of cinder and iron filings were carefully 
laid on the leaves and allowed to remain for several days. No 
reaction of any sort occurred among the hairs of the leaves. 
SUMMARY 
One of the most interesting results was the chemotactic re- 
action of the leaf hairs. This was very distinct in every case, 
excepting experiment 6. ) 
The experiments proved that the leaf hairs are capable of 
exerting a distinct solvent action on the organic matter placed 
on them. Experiments 2, 3 and 4 show this. This solvent action 
does not serve to remove any objectionable organic matter but 
the plant profits by the food derived by this action. The latter 
is well shown from the observations made, especially those of 
experiment 5. No experiment showed the leaves suffering from 
the presence of small amounts of organic matter on their leaves 
and on the contrary the leaves thus treated were the last to lose 
the green color as in experiment 5. The Salvinia may get only 
a small quantity of food in this way, as is indicated by the rapid 
decline of the plants even in experiment 5 when placed in a solu- 
tion free of potassium nitrate. The positive chemotaxis of the 
leaf hairs, the solvent action on the cubes of cooked white of egg 
and the discoloring of the yellow of the raw egg coupled with the 
fact that in the normal habitat this fern frequently has the bodies 
of small soft insects which are finally dissolved on its leaves, 
shows at least that some food is taken in by these leaves when it 
is offered. : 
INDIANA UNIVERSITY, BLOOMINGTON 
w 
