20 



of the . . . processes nuist be based, therefore, upon the manner in 

 which these agencies affect the . . . materials. . . . Constructive and 

 destructive agencies can be recognized only when the phenomena are 

 made the basis for the scheme. Processes are merely operative. If 

 coupled with products at all, in classification, all must be regarded as 

 formative or constructive. The product's destruction, its loss of iden- 

 tity, is wholly immaterial. The action of agencies is merely to pro- 

 duce constant change." 



Van Hise ('04) has formulated other principles of the process 

 method as follows : 



"The agent is the substance containing energy which it expends in 

 doing work upon other substances. The substance upon which work is 

 done may thereby receive energy, and thus become an agent which 

 does work upon other substances ; and so on indefinitely. Indeed, the 

 rule is that one process follows another in the sequence of events, until 

 the energy concerned becomes so dispersed as to be no longer trace- 

 able. Theoretically this goes on indefinitely. . . . We have seen that 

 the action of one or more agents through the exertion of force and the 

 expenditure of energy upon one or more substances is a geological 

 process. It is rare indeed, if it ever happens, that a single agent works 

 through a single force upon a single substance. ... If geology is to 

 be simplified, the processes must be analyzed and classified in terms of 

 energies, agents, and results. Each of the classes of energy and agent 

 should be taken up, and the different kinds of work done by it dis- 

 cussed. . . . The general work of each of the agents and the results 

 accomplished should be similarly considered. Not only so, but the 

 work of the different forms that each of the agents takes should be 

 separately treated. Thus, besides considering the work of water gen- 

 erally, the work which it does both running and standing must be 

 treated. The first involves the work of streams ; the second, the work 

 of lakes and oceans. This involves the treatment of streams as enti- 

 ties. . . . The treatment of the agents will be more satisfactory in pro- 

 portion as the work done by each of the forms of each of the agents 

 is explained under physical and chemical principles in the terms of 

 energy." 



Viewed from this standpoint it is remarkal)le how many of our 

 current zoological conce|)tions are essentially static, and how confused 

 are our conceptions of the process method. Physiology is supposed 

 to be devoted solely to processes, yet physiologists use the terms anab- 

 olism and katabolism, constructive and destructive influences, and, 

 likewise, zoologists frequently use the expressions "the friends" or 

 "the enemies" of animals — a dual terminology which has a certain 



