532 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



streams as entities. * * * The treatment of the agents will be more satis- 

 factory in proportion 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 remarkable how many of our 

 current zoological conceptions are essentially static and how con- 

 fused are our conceptions of the process method. Physiology is 

 supposed to be devoted solely to processes, yet physiologists use the 

 terms anabolism and katabolism, constructive and destructive in- 

 fluences, and, likewise, zoologists frequently use the expressions " the 

 friends" or "the enemies" of animals — a dual terminology which 

 has a certain utility but which exists mainly on account of the static 

 conceptions of organic relations. 



The dynamic or process concept is a difficult one to attain, and to 

 apply in all cases, as any one will soon learn if he strives to do this 

 consistently; and yet as a scientific ideal there can be no doubt that it 

 has the same superiority over the older static methods and point of 

 view that an explanation has over an empirical description. 



3. DYNAMIC AND GENETIC CLASSIFICATION OF ENVIRONMENTS. 



In the natural history sciences we have two main sorts of classifi- 

 cations of phenomena, those which we call " natural " and those 

 which we call " artificial." Natural classifications are those in which 

 the basal criteria are of origin, the method of processes or genesis. 

 A classification of lakes upon the basis of the processes which 

 operated in their origin — crust al movements of the earth, the mean- 

 ders of streams, the w 7 ork of an ice sheet, volcanic activity, etc. — 

 would at the same time furnish an explanation of them in terms of 

 their origin. Artificial classifications are those in which the criteria 

 are arbitrarily chosen. Any character may be made the basis for an 

 artificial classification. Thus lakes may be classified upon the basis of 

 their size, depth, color of the water, distance from cities, number of 

 boats upon them, etc., but such classification would not furnish the 

 basis for a scientific explanation of lakes. The artificial is often use- 

 ful or convenient for a special purpose; the genetic is illuminating 

 from the standpoint of scientific Interpretation. This method may be 

 applied to any kind of environment, physical, physical and biological 

 combined, or solely biological. To the degree that the environment is 

 dominated by the physical conditions the laws of physical change 

 and physical genesis will preponderate in the origin of such environ- 

 ments, and corresponding relations apply to biological environments. 



The dependence of the genetic method upon causes and conditions 

 makes it impossible to divorce it from the local conditions. This is 

 at once the strength and weakness of this method, for it is particular, 

 and generalized averages mean little because origins are different un- 



