22 THE ORIGIN OF THE NERVOUS SYSTEM 



organismic when it exists. Moreover, it is not primarily 

 the material exchange between protoplasm and environ- 

 ment, but the ordering and controlling of this change in 

 definite ways which constitute the fundamental charac- 

 teristic of organismic pattern. In short, however it 

 may arise, organismic pattern is not simply the pattern 

 of the material exchange between protoplasm and 

 environment but rather a definite behavior pattern of 

 different regions, cells, or cell groups. The fundamental 

 factor in determining protoplasmic behavior of organis- 

 mic character is the nonspecific, quantitative factor of 

 excitation, and with excitation transmission is associated. 

 In view of all the facts, then, the logical procedure in 

 attacking the problem of the origin of organismic pattern 

 is to determine whether, or to what extent, excitation 

 and transmission are actually concerned in determining 

 this pattern. And since the data of both ontogeny and 

 phylogeny indicate that organismic pattern once estab- 

 lished undergoes progressive complication, it is evident 

 that we must first of all attempt to discover the simplest 

 terms in which organismic pattern appears in nature. 

 The following chapter is devoted to a consideration of 

 this question. 



