STONE: CONTACT STIMULATION 459 
RESPONSE OF PLANTS TO CONTACT STIMULATION WITH WIRES AND 
TWINE 
The investigations relating to the effects of contact with wires, etc., 
are given in Tables 2-9. All of these experiments were made in a 
well-lighted conservatory, the plants being grown in a good uniform 
grade of loam either in solid beds or in benches. In this series I-6 
plants were enclosed by wires, or dowels, and twine, and in some 
cases only fish netting was employed. The normal plants were in some 
instances grown free from contact with one another and in others not. 
In the case of only a single plant being surrounded by wire netting 
contact would occur only with the wire, whereas when two or more 
Fic. 3. Showing growth of castor beans in contact and not in contact with 
wire netting. Plants removed with as little disturbance as possible from original 
position for photographic purpose. 
plants were grown tolerably close together they would eventually be 
in contact with each other as well as with the wire netting, etc. Hence 
contact stimulation would result not only from the use of wires, etc., 
but from the contact of plants with one another, or in other words the 
so-called normal plants were not in all instances free from contact, 
inasmuch as when they were grown in groups they would eventually 
touch one another and growth would be influenced. We therefore 
have two series of experiments, namely: (a) those in which the 
