December 20, 1912] 



SCIENCE 



855 



history and ontogenetic history. We con- 

 ceive of phylogeny as working from the 

 simple to the complex. An original an- 

 cestor gives rise to series of animals which 

 inherit peculiarities of the common ances- 

 tor and acquire various additional pecul- 

 iarities. It is a process of differentiation. 

 The oosperm is the original ancestor of all 

 the cells of the individual. Ontogeny 

 works from the simple to the complex. As 

 it progresses cells "inherit" certain pe- 

 culiarities from the common ancestor, the 

 oosperm, and "acquire" other peculiarities 

 which, so far as visible structural features 

 are concerned, are new for that individual. 

 Thus arises differentiation into the numer- 

 ous types of tissue cells. (It is a curious 

 inconsistency of the scientific mind that in 

 ontogeny, where we can directly observe 

 the history of the whole "race" of cells, 

 having before us both the beginning and 

 the end of their evolution, we are strongly 

 inclined to believe that the "new" char- 

 acters which appear as differentiation 

 progresses were somehow potentially pre- 

 sent in the common ancestor, the oosperm. 

 Turning from this evolution of a cell king- 

 dom to that larger evolution of an animal 

 kingdom whose beginning and end we can 

 not compass, of whose history only a brief 

 and far from lucid chapter lies within our 

 observation, we are equally strongly in- 

 clined to look for the causes of new char- 

 acters anywhere under heaven rather than 

 to attempt to think of them as having been 

 somehow latent in a remote ancestor!) 



In spite of striking analogies, phylogeny 

 and ontogeny are quite clearly different in 

 their mode of operation. The noteworthy 

 feature of ontogeny is the concerted and 

 coordinated behavior of many elements, 

 either of the same kind or of different 

 kinds. This harmonious action of ele- 

 ments gives rise to configurations which 



are definite and limited. "Within phylo- 

 genetie groups such coordinated behavior 

 of numerous individuals does not, ip gen- 

 eral, exist. "We see something similar to it 

 in the social organizations of some animals, 

 but outside of the human species it is ex- 

 ceptional. "Within the human species so- 

 cial organization is all-important. There 

 are conspicuous analogies between the co- 

 ordinated behavior of human individuals 

 and the concerted action of the structural 

 elements of an individual. "We may well 

 raise the question whether an unprejudiced 

 and open-minded study of these analogies 

 may not serve to guide us toward the truth 

 in our attempt to interpret and "explain" 

 the organization which we see within the 

 individual. For the single cell and the 

 whole multicellular animal are both living 

 beings of one kind or another. This brings 

 us to the edge of a vast subject whose full 

 discussion at this point would be both pre- 

 mature and aside from our main thesis. 



In general, then, phylogenetic groups 

 lack organization. They possess no form 

 unless it be geographical distribution, and 

 this, even were our knowledge of it com- 

 plete, must be so indefinite that it can be 

 described only by means of arbitrarily 

 drawn lines. In geographical distribution 

 there is nothing closely comparable to the 

 problem of form within the individual. 

 Distribution has its problems, but the fac- 

 tors in it are relatively well known and 

 intelligible. In general they consist, upon 

 the one hand, of the various conditions 

 contained within the physical environment 

 and, upon the other hand, of the peculiari- 

 ties in the organization of the individuals 

 of the group. But these are the peculiari- 

 ties of the organization of the individual 

 as an individual. So far as form is con- 

 cerned, and aside from the relatively rare 

 phenomena of social organization, there is 



