22 Journal of Comparative Neurology. 



because the former grows accustomed to observe the close cor- 

 relation between structural differences and conscious experience 

 whose dynamic nature it is impossible to doubt. There can be 

 no more doubt that the morphological peculiarities of nervous or 

 other tissue are the expression of the equilibrated forces of 

 growth and other functions than that the form and polariscopic 

 qualities of a crystal represent molecular reactions. It is also ap- 

 parent that the concept of matter in either case helps not at all 

 in the explanation of these forces and that the attribute of ma- 

 teriality is to be determined on independent grounds. Not to 

 discuss the ontological question at this time, it may simply be 

 said that in our use of the morphological terms it is only with 

 the reservation that they are convenient expressions to define 

 the constant elements in our experience of dynamic forms. 

 There are many advantages in this more direct interpretation of 

 vital phenomena, for by the interpolation of imaginary material 

 elements between the objective force and the subjective experi- 

 ence one loses sight of the constant dynamism — a dynamism 

 which does not make necessary a fresh explanation of each new 

 expression of force ; for the existence of force may be regarded 

 as self-evident when we recall that activity is the sole element 

 of experience, and its varying forms are, in a sense, the alge- 

 braic expressions for interactions. The whole question of troph- 

 ism is robbed of most of its difficulties if we think of structure 

 as not a thing dissimilar from function, but consider both as dif- 

 ferent expressions of similar forces. 



It would seem that especially in the sphere of embryology 

 we should be ready for the abandonment of the fruitless search 

 for material grounds for persistence of type. The theory of 

 pangens is one illustration out of many of the absurdities to 

 which a materialist construction is driven. The observed con- 

 formity to type observed in each of the thousand plants which 

 may arise by minute subdivision of a moss, for example, shows 

 how hopeless is the attempt to base on any specific material the 

 capacity for heredity, no matter how eked out by the doctrine 

 of latency. Correspondence in mode is the condition of iden- 

 tity implied by a dynamic theory, and the heterogeneity ex- 



