THE PROBLEM OF PATTERN 21 
else it must be dependent upon a non-mechanistic 
principle, as the vitalists maintain. 
CONCLUSION 
Leaving out of consideration the purely contactual 
or mechanical relation as obviously not of fundamental 
importance in this connection, there remain two chief 
categories of relation between protoplasm and its 
environment, the material or chemical and the dynamic 
or excitatory. These two types of relation appear in 
all organisms, the one being concerned with nutrition, 
respiration, excretion, i.e., the material exchange in 
general, the other with behavior in the broad sense. I 
have pointed out that the excitation-transmission rela- 
tion is apparently the most generalized and most 
primitive factor in organismic pattern (p. 17). Lest 
this statement be misunderstood it may be pointed out 
that it does not mean that in the relations between 
protoplasm and the environment excitation is any more 
primitive or fundamental than the material relation. 
Material exchange between protoplasm and environ- 
ment is of course necessary for the continuance of life 
in protoplasm, and there can be no doubt that in nature 
material exchange and excitation are closely associated. 
I would merely maintain that the excitation-transmission 
relation, whether it arises in connection with material 
exchange or through a purely dynamic action of external 
factors is a more generalized and more primitive factor 
in the organismic pattern arising on the protoplasmic 
substratum. Material exchange is primarily a matter 
of protoplasmic pattern and not necessarily organismic, 
but the excitation-transmission relation is always 
