402 ON THE SUPPOSED BOTANICAL PROOFS OF THE 



to undergo a transformation corresponding to that produced by 

 the external influences ; such a transformation as would cause the 

 future organism to spontaneously develope changes similar to those 

 which its parent had acquired. But since the germ-plasm is not 

 an organism in the sense of being a microscopic facsimile which 

 only has to increase in size in order to become a mature organism, 

 it is obvious that the developmental tendencies must exist in the 

 specific molecular structure, and perhaps also in the chemical consti- 

 tution of the germ-plasm itself. It therefore follows that the changes 

 in the germ-plasm which would be required for the transmission of 

 an acquired character must be of an entirely different nature from 

 the change itself acquired by the body of the parent plant : and 

 yet it is supposed that the former is produced by the latter as a 

 result of correlation. I will illustrate this by an example. Let us 

 suppose that the influence of climate had caused a plant to change 

 the form of its leaves from an ovate into a lobate shape : now such 

 a change could not be transferred to the germ-plasm in the pollen 

 and the ovules, as anything similar to leaves or the form of lea v is : 

 for such specialized morphological features have no existence in the 

 germ-plasm. The only thing which could happen would be changes in 

 its molecular structure which bear no resemblance to those changes 

 which are implied by the direct alteration of the form of the leaf 

 in the parent plant. Any one who clearly appreciates this difficulty 

 will hesitate in admitting the possibility of the transmission of 

 acquired characters, because it is possible that the sexual cells may 

 be affected by correlated influences. If the change in the form of a 

 leaf exercises any influence at all upon the germ-plasm, why should 

 it produce a corresponding (in the above-mentioned sense) change 

 in its molecular structure ? Why should it not produce some other 

 out of the immense number of possible changes ? There must be as 

 many possible changes in the structure of germ-plasm as there are 

 possible variations in each part of a plant that arises from it. AVhy 

 then should the corresponding change always occur, a change 

 which had never previously existed in the whole phyletic develop- 

 ment of the organic world ; for the plant with the latest modifica- 

 tion can have never existed before ? The occurrence of a particular 

 change out of the countless possible changes would be about as 

 likely as if one out of a hundred thousand pins thrown out of a 

 window were to balance on its point when it reached the ground. 



