WEISMANN'S THEORY OF THE GERMPLASM 87 



are continually growing and changing at the ex- 

 pense of the surroundings. 



Now, let one reflect that the egg and the adult 

 are two terminal states of organised material, and 

 that they are separated from each other by an 

 almost inconceivably long series of connecting, 

 intermediate states ; consider that each stage of 

 the development is the rudiment and the producer 

 of the succeeding stage, of the stage that follows, 

 as the consequence of it ; consider that what was 

 external in each antecedent stage has entered the 

 rudiment and become part of it in the succeeding 

 stage. Then it will be understood that it is a 

 logical error to assume that all the characters 

 present in the last link of the chain of develop- 

 ment have their determining causes in the first 

 link of the chain. The mistake lies in this : in 

 the failure to distinguish between the causes con- 

 tained in the egg at the beginning of the develop- 

 ment, and the causes entering it during the course 

 of development from the accession of external 

 material in the various stages. As there can be 

 no absolute identity between rudiment and pro- 

 duct, it is erroneous to transmute the visible com- 

 plexity of the final stage of the development into 

 an invisible complexity of the first stage, as the old 

 evolutionists did, and as the new evolutionists are 

 attempting to do. 



But there is another error in the doctrine of 

 determinants. This is in intimate union with the 

 error just discussed, and, to put it shortly, consists 

 in attributing to a cell and the egg and sperma- 



