ON BIOLOGICAL EVOLUTION 7 



ties, the dynamic and formative powers of the unal, or 

 dual, nervous systems are responsible for the direction 

 and administration of the alien influences at work, and for 

 the accomplishment of their final results, be they innocent 

 or malignant. Appeals, therefore, must be made to them 

 individually or conjointly, in accordance with the indica- 

 tions for treatment deducible in each individual case. 



