Ryder.] i Ji [April 7, 



as developed in tlie motions of organisms and their parts as an agency in 

 the modification of the forms and proportions of their hard parts. In 

 tliis he has distinctly followed Lamarck, Spencer and the writer, and to 

 tills agency he has applied the terra Jciaetogenesis, which may also be 

 written kinetogeny in order to make its Anglican spelling conform to that 

 of the very useful terms proposed by ILeckel. 



Unfortunately this term, kinetogeny, does not embrace a consideration 

 of all the forms of energy that concern the problem of adaptation. My 

 only reason, therefore, for invading this field of terminology is that there 

 appears to be a need for another term which shall be more comprehensive 

 and which shall apply to all the forms of energy involved in a study of 

 adaptive processes, namely, the potential or static and the actual or 

 kinetic. This will embrace both the energy of rest or equilibrium and 

 that of motion or lack of equilibrium. The most general term that can 

 be used for this purpose seems to be ergogeny, the etymology of which is 

 apparent. This general term, ergogeny, will include not only kinetogeny, 

 but also its antithesis, statogeny. 



If an organism suflFers morphological modification in consequence of 

 the display of the energy of motion, any modification thus caused would 

 be developed kinetogenetically. If, on the other hand, an organism were 

 modified in such a way that the energies developed by it were in a condi- 

 tion of statical equilibrium, and, moreover, if its specific form depended 

 upon the maintenance of such a statical balance, then any formal modifi- 

 cation thus caused and maintained would be developed statogenetically. 

 If it is meant that energy has been c.mcerned in producing a certain mod- 

 ification without specifying the kind of energy, such modification may be 

 said to have been produced ergogeneticaUy. Concrete illustrations will, 

 liowever, be necessary in order to give a clear notion of the very real dif- 

 ference that exists between the two processes, namely, kinetogeny and 

 statogeny, embraced under the still more general term of ergogeny. 



If the motion of the developing parts of an organism condition their 

 structural modification in a definite and precise way, as in the case of the 

 development of vertebral centra, of the vertical rows of scales on fishes, 

 or the fractures across the fin rays of certain fishes, as I have shown else- 

 where,* then the effects so produced are developed ergogeneticaUy. In 

 that such effects are the result of the expenditure of energy in the form 

 of motion they are also developed kinetogenetically. 



If, on the other hand, the process is one in which the energy developed 

 is a consequence of growth itself, and is dependent merely upon the gross 

 physical and statical properties of the living matter itself, such as the 

 varying surface-tension of different parts of the surface of the plasma, 

 then the problem becomes one, not of motion, but of the want of motion, of 

 forces in equilibrium or a statical one. Such conditions of statical equi- 

 librium of surface-tensional forces of the adjacent surfsices of the cells of 



*" Proofs of the Effects of Habitual Use in the Modification of Animal Organisms," 

 Proc. Amer. Philos. Soc, Vol. xxvi, Nov. 21, 1889. 



