Septembeb 7, 1906.] 



SCIENCE. 



305 



viromnent which may intensify the normal 

 inequalities of individuals (variation), as well 

 as from accidents of geographical distribu- 

 tion by which groups of individuals may be 

 subdivided (speciation). All these are evolu- 

 tionary matters in the general sense already 

 alluded to, but underneath all the multiplicity 

 of more or less pertinent data and speculations 

 is this process of change in species. It may 

 be denied, as in the mutation hypothesis of 

 Professor de Vries, that there is such an evo- 

 lutionary motion of specific groups, but all 

 will be ready to admit that if such progressive 

 changes of species take place they represent 

 the real center and essence of the subject of 

 evolution, the physiological process of which 

 it is of so much importance to know the con- 

 ditions and causes. 



The fact that evolutionary literature has 

 become so vast a congeries of speculations 

 should not make us forget what it is all about. 

 Certainly it affords no sufficient reason for 

 avoiding the use of the word evolution in 

 describing a conception in which a continuous 

 modification of the specific type is treated as 

 a normal condition and requisite of organic 

 existence. 



After writing the above I have come upon 

 a further article by Dr. Ortmann in Science 

 of June 22, in which he appears reconciled to 

 the new term speciation, in spite of the hoary 

 antiquity and other objectionable features of 

 the idea which led to the suggestion. This is 

 very gratifying. But at the same time it 

 becomes even more obvious than before that 

 the title of Dr. Ortmann's previous article 

 was misleading, for in this last review of de- 

 velopmental theories he leaves out of account 

 altogether the very conception he has so re- 

 cently claimed to discuss, a conception which, 

 whether old or new, true or false, is radically 

 diverse from any of the alternatives treated. 

 The distinction of speciation from evolution 

 has been taken, evidently, as the whole * con- 

 ception,' whereas it is only an incidental fea- 

 ture. The mistake is due, no doubt, to my 

 continued failure to give the kinetic point of 

 view an adequate presentation, but it may be 

 that the discussion has now reached a stage 



where the distinctions can be outlined more 

 clearly than before. 



Without denying the general literary sense 

 in which anything which has even a remote 

 bearing or influence on evolution may be con- 

 sidered a factor, we may return once more to 

 the kernel of the whole matter, the question 

 of the true, actuating causes of evolution. 

 The differences between the alternative inter- 

 pretations may then be definitely located. 



It is evident that Dr. Ortmann is discussing 

 a generalized abstraction compounded out of 

 the four factors or groups of phenomena, vari- 

 ation, inheritance, adjustment and speciation. 

 The kinetic conception, on the other hand, 

 treats evolution as a concrete process, carried 

 forward through two factors which are very 

 different from the other four, since they are 

 resident in species and do not depend upon 

 environmental influences. Dr. Ortmann's un- 

 willingness to recognize evolution as a con- 

 crete process can now be understood, for the 

 factors upon which he relies are incapable of 

 explaining such a process, as a brief examina- 

 tion will show. 



Inheritance, to take the oldest idea first, is 

 a general condition of organic existence, but 

 it has no evolutionary implication. If there 

 were no inheritance there would be, of course, 

 no evolution in the biological sense, but this 

 is no indication that inheritance causes evolu- 

 tionary progress. Many writers have consist- 

 ently denied that inheritance causes, or tends 

 to cause, evolution. They hold, on the con- 

 trary, that like would produce like indefinitely 

 unless acted upon by disturbing agencies of 

 the environment. Adaptation or adjustment 

 to environment, whether by natural selection 

 or otherwise, is not a cause of evolution, but 

 rather a result, a meeting by evolutionary 

 processes of requirements imposed by external 

 conditions. Speciation, or the diversification 

 of segregated groups of organisms, is also 

 clearly an evolutionary result instead of a 

 cause. Even variation, in the sense in which 

 the word appears to be used by Dr. Ortmann, 

 to indicate the effects of external influences 

 upon organisms, has not been shown to have 

 any connection with evolution, notwithstand- 



