WHAT IS EVOLUTION? 731 



type, some cells advance to the dignity of brain-cells, whose function 

 is somehow connected with the generation or at least the manifestation 

 of thought, will, and emotion ; other cells descend to the position of 

 kidney-cells, whose sole function is the excretion of urine. But here, 

 also, the highest cells are successively higher, and the whole aggre- 

 gate is successively nobler and more complex. It is again a branch- 

 ing and rebranching in every direction, some going upward, some 

 downward, some horizontally, anywhere, everywhere, to increase the 

 complexity of relations internal and external, and therefore to elevate 

 the plane of the whole. 



Lastly, the law of cyclical movement is also a law of ontogeny and 

 therefore of evolution. This law, however, is less fundamental than 

 the other two, and is, therefore, less conspicuous in the ontogenic than 

 in the phylogenic series. It is conspicuous only in the later stages of 

 ontogeny and in other higher kinds of evolution, such as social evolu- 

 tion. For example, in the ontogenic development of the body and 

 mind from childhood to manhood we have plainly successive culmina- 

 tions and declines of higher and higher functions. In bodily develop- 

 ment we have culminating first the nutritive functions, then the repro- 

 ductive and muscidar, and lastly the cerebral. In mental development 

 we have culmination first of the receptive and retentive faculties in 

 childhood, then of imaginative and aesthetic faculties in youth and 

 young manhood ; then of the reflective and elaborative faculties the 

 faculties of productive work in mature manhood ; and, finally, the 

 moral and religious sentiments in old age. The first gathers, and 

 stores materials ; the second vivifies and makes them plastic building 

 materials ; the third uses them in actual constructive work in build- 

 ing the temple of science and philosophy ; and the fourth dedicates 

 that temple only to noblest purposes. 



Observe here, also, that when each group of faculties culminates 

 and declines it does not perish, but only becomes subordinate to the 

 next higher dominant group, and the whole psychical organism be- 

 comes not only higher and higher in its highest parts, but also more 

 and more complex in its structure and in the interaction of its corre- 

 lated parts. 



Observe, again, the necessity laid upon us by this law the neces- 

 sity of continued evolution to the end. Childhood, beautiful child- 

 hood, can not remain it must quickly pass. If, with the decline of 

 its characteristic faculties, the next higher group characteristic of 

 youth do not increase and become dominant, then the glory of life is 

 already past and deterioration begins. Have we not all seen sad ex- 

 amples of this ? Youth, glorious youth, must also pass. If the next 

 higher group of reflective and elaborative faculties do not arise and 

 dominate, then progressive deterioration of character commences here 

 thenceforward the whole nature becomes coarse, as we so often see 

 in young men, or else shrivels and withers, as we so often see in young 



