626 THE AMEBIC AN NATURALIST [Vol. LI 



bearing upon the evolution of the paired limbs or upon 

 the evolution of the vertebrate skull, or of the carnassial 

 teeth of Carnivora, they would, I believe, be forced to ac- 

 cept the principle of the progressive efficiency of struc- 

 tures for special functions as at least a fruitful working 

 hypothesis. 



A distrust of the word "adaptation," which has been 

 in the bad company of the Lamarckian theory, is appar- 

 ently revealed in Professor T. H. Morgan's ''A Critique 

 of the Theory of Evolution" (1916). The author, how- 

 ever, apparently favors the idea of natural selection 

 operating upon "advantageous" or "beneficial muta- 

 tions" and eliminating the "injurious effects" of other 

 mutations. Of course if "adaptation" really implied an 

 acceptance of the Lamarckian theory it would be better 

 to use some such phrase as "progressive functional ad- 

 justment," but the important point to bear in mind is that 

 nature has produced myriads of structures which have a 

 very definite functional adjustment with other structures, 

 in other parts of the body, or with parts of other bodies, 

 or with parts of the environment. And it is perfectly 

 plain from the evidence of comparative anatomy and 

 paleontology'- that functionally correlated parts have often 

 evolved together, and with definite reference to each 

 other, let the explanation of that fact be what it may. 

 Professor Morgan himself has fully recognized this fact 

 in his address^ entitled "Chance or Purpose in the Origin 

 and Evolution of Adaptation." 



The second idea which seems to be implied by Professor 

 Bateson, and which I have heard certain university stu- 

 dents express, is that phylogenetic "speculations" are un- 

 verifiable, because "control experiments" are not pos- 

 sible. By similar reasoning geological theories concern- 

 ing the history of the earth, archeological theories con- 

 cerning the history of peoples, and all historical studies 

 based upon internal or circumstantial evidence are equally 

 untrustworthy. The answer to such a theoretical objec- 

 tion, if it were definitely made, would be that comparative 



