ii POTENTIALITY IN GERMS 115 



Radiata, and one for the Insecta. Let 

 us assume, farther, on the same footing, 

 that from each of these germs all the 

 modifications belonging to each class 

 have been developed by what we call 

 the processes of ordinary generation. 

 Then it follows that, as all these modifi- 

 cations have undoubtedly taken definite 

 directions from invisible beginnings to 

 the latest results and complexities of 

 structure, the original germs must have 

 been so constituted as to contain these 

 complexities, potentially, within them- 

 selves. This conclusion is not in the 

 least affected by any influence we may 

 attribute to external surroundings. The 

 Darwinian school in all its branches in- 

 variably dwell on external conditions as 

 physical causes. But it is obvious that 

 these can never act upon an organic 

 mechanism except through, and by means 

 of, a responsive power in that mechanism 



