316 REV. J. T. GFLICK OK 



pointed out, and many writers have failed to observe that natural 

 selection often produces fixity of type instead of transformation, 

 and that divergence in the kinds of natural selection depends 

 on Segregation, and not necessarily on exposure to different 

 environments. 



Assimilational, Stimulational, Suetudinal, and Emotional Trans- 

 formation belong to a class of principles that have sometimes been 

 grouped under the term Variation, while Selectional,Eliminational, 

 Amalgamational, and Eecundal Transformation may be classed as 

 principles of Uiihalanced Propagation. It should, however, be 

 carefully noted that Variation usually indicates deviation from the 

 average, an entirely difi'erent factor from those which relate to the 

 change of the average itself. It may therefore be well to group 

 these first four principles as principles of Involution. The 

 principles of Unbalanced Propagation are abundantly established 

 as genuine methods of change in the average inheritable characters 

 of species, not only by experience derived from the domestication 

 of plants and animals, but by observation of similar effects pro- 

 duced by natural processes. On the other hand, the principles of 

 Involution, though very marked in their influence on individual 

 character, cannot be easily tested as to their efiects on the inherit- 

 able characters of species. Weisraann maintaiiis that acquired 

 characters cannot be inherited. If this is so, there can be no 

 involution of specific characters, and the only factors in mono- 

 typic evolution are the causes whose laws of action are expressed 

 in the principles of Unbalanced Propagation. 



I have not mentioned " Acceleration and E-etardation " as 

 principles of transformation, for they seem to be but phases of 

 the law of Suetude ; for, as explained by Cope, the former is the 

 effect of Use or Effort in the parents, producing in the offspring 

 accelerated inheritance, while the latter is due to Disuse or Ces- 

 sation from Effort, producing in the offspring retarded inheri- 

 tance *. So also Hyatt's " law of Concentration " (or " Accele- 

 ration," as he often calls it) seems to be a general law of inheri- 

 tance relating to the transmission of characters originating under 

 any and every principle, the effects, whether progressive or retro- 

 gressive, being inherited at earlier and earlier ages in each suc- 

 cessive generation t. It is also doubtful whether Correlated 



» ' Origin of the Fittest,' pp. 203-7, 228. 



t 'Proceedings of the American Association,' toI. xxxii. pp. 852-361. 



