ASPECTS OF KINETIC EVOLUTION 343 



nomena to positional or other relations of molecules or atoms of 

 the cerebral tissues, but impossible to imagine an adequate nexus 

 of association with the concrete facts, actions or functions. The 

 opinion has already been recorded in another place that truly 

 mechanical solutions of this series of problems are likely to 

 await the recognition of additional properties of matter, which 

 physical researches are now revealing with such startling 

 rapidity. 1 As clearly perceived and definitely stated by Lord 

 Kelvin, the current conceptions of physics are not adequate for 

 the treatment of the problems of biological evolution. 



The wonderful and altogether unexpected results of studies 

 of the internal structures of cells are but poorly appreciated by 

 those whose hopes have dwelt on the discovery of mechanisms 

 of heredity. From the morphological standpoint it may appear 

 that little has been obtained except to open another chapter in 

 the vast complexity of nature. The internal organs and proc- 

 esses of cells have their multifarious similarities and diversities, 

 like all other phases of organic existence. Reproduction is 

 carried on by as many different methods as assimilation, res- 

 piration or locomotion. The great and surprising result of 

 cytological investigation is not in learning that such diversity 

 exists, which might have been anticipated, but in ascertaining 

 that the evolution of the large and complex bodies of the higher 

 plants and animals has been made possible by the evolution of 

 superior methods of reproduction. Mechanical theorists have 

 been so intent on finding a mechanism of heredity that they 

 have failed to recognize the physiological significance of an 

 improved process of conjugation. 



The older idea was that reproduction, that is, the production 

 of a new individual plant or animal, followed the conjugation or 

 complete union of the parental germ-cells, but it has been found 

 that this is not true of any of the higher types of life. What 

 has been considered conjugation among the higher groups, that 

 is, the process in which the characters of the new organism are 

 determined — as far as they are determined in the germs — is 

 not a complete conjugation of the germ-cells, but only the begin- 

 ning of a conjugation which continues throughout the life of the 

 new individual. 



^ook, O. F., 1904. Evolution and Physics. Science, N. S., 20: S7. 



