Inheritance in Unicellular Forms 209 



paleontology has demonstrated in so splendid a manner, 

 of the gradual modification of certain parts through long 

 geologic ages toward ideals of mechanical perfection, 

 for example, of the gradual perfecting of the skeletal 

 articulations? Not only does the post-Darwinian school 

 afford no explanation of this but with the acceptance of 

 its theories this progress is indeed impossible." 158 



And Osborn's view is similar. "Living matter," 

 writes he, "is characterized by a capacity of adaptive or 

 purposeful reaction. If this capacity is inherited in the 

 Protozoa, thanks to the simplicity of their process of 

 propagation, it must be the same in the Metazoa. For 

 each newly developed metazoon which retains the advan- 

 tage of the inheritance of the adaptive reaction would 

 be preserved, while each individual which loses this would 

 degenerate. The mechanism of the inheritance of onto- 

 genic adaptation must then have been developed in 

 passing from the unicellular to the pluricellular forms 

 by means of natural selection." 159 



Weismann it seems to us could reply only by saying 

 that natural selection may not have established the inher- 

 itance of acquired characters in the pluricellular forms 

 also, because the production of the mechanism neces- 

 sary for that purpose had become materially impossible 

 by reason of the structure of the metazoic organism. 

 But this assertion, which would limit the capacities of 

 living organic substance, must appear a little too hazard- 



158 Cope : The mechanical Causes of the Development of the hard 

 Parts of the Mammalia. Journ. of Marph., vol. VIII, No. 2, Boston, 

 U. S. A. Ginn, Sept. 1889. P. 140141. 



18 Osborn : Alte und neue Probleme der Phylogenese. Ergebnisse 

 der Anatomic und Entwicklungsgeschichte, herausgegeben von Mer- 

 kel und Bonnet. Band. III. 1893. Wiesbaden, Bergmann, 1894, 

 P. 607. 



