A DYNAMICAL HYPOTHESIS OF INHERITANCE. 51 



aggregate as a mechanically constructed system during life and 

 development, through growth and metabolism, must maintain 

 the shapes of organisms as we see them. The epigenetic theory 

 of inheritance therefore promises us a secure basis upon which 

 to found a theory of the mechanics of development, as well as 

 a theory of the origin of morphological types. The theory of 

 life may indeed be regarded as having its foundations in cellu- 

 lar, inter- and intra-cellular mechanics and dynamics as con- 

 ditioned by ontogenetic metabolism. The fact that centrosome, 

 nucleus, and cytoplasm are represented almost coextensively 

 with the presence of life itself is proof that the fundamental 

 machinery of organization must be the same in the principles of 

 its action, no matter how widely its forms may differ from one 

 another. 



The theory that the surface layer of molecules of organisms, 

 whether interior or exterior, are in equilibrium also carries with 

 it the idea that the configuration of all organs and organisms 

 are merely the material expression of gradually built up equi- 

 potential surfaces. This gives us a far more rational founda- 

 tion for a theory of general morphology than the hypothesis of 

 gemmaria proposed by Haacke. During growth and metamor- 

 phosis these equipotential surfaces undergo formal changes in 

 size and shape, due to the internal processes of molecular trans- 

 formation or metabolism. But such changes are continuous, 

 and one stage or form passes into the next palpable one through 

 an infinite number of slightly different forms. Examples of 

 such surfaces may be seen in any organism, vegetable or 

 animal, and at any stage of the same. The principle is there- 

 fore of universal application. 



Summary. — Preformation of any organism in the germ has 

 no foundation in fact. 



All that it is possible to account for upon the basis of a 

 theory of preformation may be much more logically and scien- 

 tifically accounted for upon the ground of dynamical theory. 

 Such a theory must deny the existence of separate corpuscles 

 or gemmules of any sort in the germ, whose business it is to 

 control development. All that is required is the assumption 

 of a determinate ultra-microscopic molecular mechanism, the 



