ON P ATIIOLOG IC AL STATES IN EVOLUTION. 



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14. The Function of Pathological States in Evolution. 

 By Mokley Roberts*. 



[Received May 7, 1918 : Read June 11, 1918.] 



That dissatisfaction with much orthodox biological opinion is 

 growing can hardly be denied. Not a little of this feeling is 

 due to the fact that what is often given as explanation cannot 

 be resolved into factors capable of appreciation, and, possibly, of 

 measurement, by the intellect. The theory has to be accepted 

 as more or less a matter of "faith. Where there is a general 

 tendency to rely on authority, speculation is discouraged, for 

 orthodoxy everywhere rests on the native conservatism of man, 

 and even the revolutionary is capable at last of fatigue. As a 

 result, tentative hypotheses offered by the great leaders tend to 

 become objects of faith, and among their less enterprising- 

 followers there arises a more or less fervent conviction that, 

 however unsatisfactory they appear now, they will presently 

 become demonstration. Thus the theory of the germ-plasm, 

 even in its later modified form, seems held too dogmatically by 

 many : the ' nature ' of inherited living matter accounts for 

 every organ as it appears ; while all changes are due to obscure 

 variations of an advantageous kind which give the survivors in 

 the struggle a better chance. On analysis, such opinions do not 

 seem truly scientific, for the " nature " of the germ-plasm can 

 barely be distinguished from the directing entelechy of Driesch, 

 and if the Weismannian cloud of ids and biophors is now 

 somewhat condensed, the magic determinant still remains in a 

 concealed vitalism which is exactly analogous, as regards the 

 organism, with pantheism as regards the universe. Nor, if we 

 are told with certainty that altered characteristics are not trans- 

 mitted, is the theory of small advantageous variations much more 

 satisfactory, if we know neither how they come, nor how they 

 are inherited. To say so much must not be regarded as treating 

 with disrespect its great author, without whom we might still be 

 wandering in the barren field of teleology. 



To regard these theories as hasty and, perhaps, unsound 

 explanations is not to accept without scrutiny the theory 

 of the transmission of acquired, or modified, characteristics. 

 Though this is a view that can be defended on the physico- 

 chemical grounds of catalysts which are measurable determinants 

 of a really scientific order, experiments to prove the fact must 

 take a very long time, and we are compelled to rely on other 

 methods of proof. That the experiments of Tower and Kam- 

 merer, for instance, suggest the transmission of modifications 

 cannot be denied. Such as oppose the general view that the 

 environment has thus an inheritable moulding influence on the 

 organism, seem to reply that these are only rare and doubtful 



* Communicated by the Secretary, 



