A DYNAMICAL HYPOTHESIS OF INHERITANCE. 39 



vided the conditions for the continuous or interrupted produc- 

 tion of germinal matter. 



The nearest approach to a condition of continuity of germi- 

 nal matter is found in the tissue of the "growing points" of 

 plants, where, as in the banana, it has maintained its unabated 

 vigor for probably not less than two thousand years without 

 the help of sexual reproduction. In many organisms the 

 germinal elements must grow and become mature. While in 

 the immature state they do not, for the moment, have the 

 latent potentiality of germs that can, then and there, develop, 

 but may even be destroyed phagocytically, or absorbed by 

 other non-germinal tissues. In still other cases there is no 

 proof that the germinal matter is differentiated, as a complete 

 mechanism, from the first stages of ontogeny onwards, so that 

 the theory of its continuity is not only not always true but is 

 also of small importance. At any rate, it is of far less import- 

 ance than the fact of continuous metabolism and the gradual 

 advent of monotropism, from a state of germinal aeolotropism, 

 effected by the dynamical processes of tissue metamorphosis 

 and specialization. 



This development of monotropism cannot take place except 

 through the sorting and grouping of specialized molecules, 

 under the domination of forces the operation of which remains 

 to be discovered in the laws of physiological chemistry and 

 molecular mechanics, and not by an appeal to an unworkable 

 hypothesis that merely covers up our ignorance and impedes 

 our progress by invoking the help of "gemmules" or " bio- 

 phors" that grow and divide like cells. There is no evidence 

 that will enable us to conceive the growth of the molecules of 

 living matter in this way, since we are now dealing with very 

 complex metameric molecular bodies, the growth and disinte- 

 gration of which is probably essentially similar to the growth 

 and solution of crystals, during the process of metabolism, 

 with this difference that growth and disintegration go on at 

 the same time in living bodies. We do not even know the real 

 nature of the chemical changes that go on in these molecules 

 and determine their structure. That the forces that do deter- 

 mine this are of a chemical nature, operating under very 



