64 THE REALM OF ORGANISMS CONTRASTED 



ing the differences so that an impression of utter discontinu- 

 ity is created. This is undoubtedly false, for organisms 

 have, as material systems, an inorganic aspect. On the other 

 hand, there is the error of exaggerating the resemblances, 

 so that we lose hold of what is distinctive in each. Let us 

 first notice some of the resemblances. 



As among plants and animals, so among lifeless things 

 there is extraordinary heterogeneity. There are over eighty 

 different kinds of elements ; the number of different minerals 

 is legion ; the multitude of the stars is untold. But, just 

 as there is in the realm of organisms the common denom- 

 inator protoplasm (or shall we say animate protoplasm?), 

 so there is in the inorganic domain an abstract common 

 denominator with a few terms, such as matter in motion 

 and ether under strain, which are not reducible to any- 

 thing simpler. The living and the not-living worlds agree 

 in showing diversity in unity, and the big generalisations 

 of Biology such as omne vivum e vivo, the hereditary rela- 

 tion, the persistence of the organism in spite of ceaseless 

 change, and so on, may be compared to the great chemico- 

 physical generalisations of the persistence of mass, of momen- 

 tum, of energy. 



What the physical irreducibles are is a question beyond 

 our scope, all that we require for our argument is the agree- 

 ment among physicists that there are but a few fundamental 

 concepts. Thus Sir Oliver Lodge declared in 1913: "Mat- 

 ter in motion, Ether under strain, constitute the fundamental 

 concrete things we have to do with in physics. The first 

 pair represent kinetic energy; the second, potential energy; 

 and all the activities of the material universe are represented 

 by alternations from one of these forms to the other '^ (1913, 

 p. 35). In terms of a few fundamental concepts, then, it 



