PHYSICAL SENSIBILITY 323 



wonderful phenomena ? Lastly, how can the feeling of existence or 

 general inner feeling give rise to a force that produces action ? 



I have conscientiously considered these matters and the wonders 

 that flow from them, and now state my opinion on the first of these 

 interesting questions. 



The faculty of receiving sensations constitutes what I call physical 

 sensibility, or feehng properly so called. This sensibility must be 

 distinguished from moral sensibility which is quite a different thing, 

 as I shall show, and which is only excited by emotions raised in us 

 by our thoughts. 



Sensations arise in us, on the one hand, from the impressions that 

 external objects make on our senses ; and, on the other hand, from those 

 made on our organs by disordered internal movements which have an 

 injurious effect and produce internal pains. Now these sensations 

 affect our physical sensibility or faculty of feeling, bring us into com- 

 munication with the outer world, and acquaint us vaguely with what 

 is happening within us. 



Let us now enquire into the mechanism of sensations, and let us 

 begin by showing the harmony which exists in all the parts concerned 

 of the nervous system, and afterwards the result on the entire system 

 of any impression on a single part of it. 



Mechanism of Sensations. 



Sensations, which by an illusion we refer to the actual places where 

 the impressions that cause them are made, are based upon a system 

 of special organs belonging to the nervous system and called the system 

 of sensations or of sensibility. 



The system of sensations is composed of two essential and distinct 

 parts, viz. : 



1. A special nucleus, that I call the nucleus of sensations, and must 

 be regarded as a centre of communication to which are conveyed all 

 the impressions which act upon us ; 



2. A large number of simple nerves which start from all the sensitive 

 parts of the body and proceed to their destination in the nucleus of 

 sensations. 



It is with this system of organs, whose harmony is such that all or 

 nearly all parts of the body share equally in an impression made on 

 any one part, that nature succeeds in giving, to all animals with a 

 nervous system, the faculty of feeling both what affects them internally 

 and also impressions made upon their senses by external objects. 



It may be that the nucleus of sensations is broken up and multiple 

 in animals which have a ganghonic longitudinal cord ; yet we may 

 suspect that the ganghon at the anterior extremity of the cord is a 



