VITAL PLASTICITY. 55 



the sliehtest reason to think that the nature of 

 these changes will ever be ascertained by phy- 

 sical investigation, inasmuch as they are cer- 

 tainly of an order or nature totally distinct 

 from that to which any other phenomena known 

 to us can be relegated. 



Lastly, it may be well to consider if our own 

 will, feelings, thoughts, emotions, hopes, desires, 

 can be expressed in force terms, or measured 

 by force standards. We are told that the 

 nervous tissue is highly plastic, the plasticity 

 being no doubt due to the property of the 

 " clay " of which it is made, by virtue of which 

 " it is not only capable of receiving and regis- 

 tering the impressions made upon it, but of 

 acquiring an instinct for complicated acts" and 

 this, Dr. Gull tells us, is " the physical basis of 

 education and of even morals !" Now where, I 

 would ask, is the lifeless clay, the inanimate 

 plastic substance, which acquires an instinct ? 

 Does not this very " plasticity " of the nervous 

 system, so different from the " plasticity " of 

 inorganic substances, remove it at once from 

 the category of the non-living ? But nerve- 

 plasticity may be yet another undiscovered 

 correlate of clay-plasticity, and both of them 



