290 MENTAL EMOTIONS. 



subsidiary spring too, derive their mechanical power originally from the 

 force which has wound up the chronometer. In this particular of the 

 storing up of power for its utilization in the time of need, the whole gan- 

 glionic or sympathetic system of nerves may be taken as the great ex- 

 ample. 



The conveyance of an impression through the great nervous centres is 

 more complicated than it is through the nerve trunks. It 



Nature of the r ./.<. 



action of nerve may be conducted, ii oi sufficient intensity, through one gan- 

 res ' glion after another in succession. The intermedium through 



which this is done is probably the nerve-tubes in a majority of instances, 

 though perhaps, in those cases in which a longer period of time is occu- 

 pied, it may be rather from vesicle to vesicle than through the tubes. 

 Impressions may be thus transferred from one set of tubes to others, or 

 Conveyance of they may be diffused from a nerve centre to many tubes 

 IhroughTn- around and so produce a wider circle of influence. That 

 tres. transfer of impressions from centripetal to centrifugal fibres 



which has been previously described as reflex action, though commonly 

 involuntary, may in many instances be governed by a direct exertion of 

 the will. Thus the respiratory movements for the introduction of air 

 may be controlled to a certain extent, as in holding the breath, but this 

 is only during a short time, for the necessity of permitting the normal 

 action to occur presently becomes insuperable. Of reflex actions, the 

 majority are obviously for the accomplishment of some special object so 

 long as the system is in health they are means for an end ; but in dis- 

 eased conditions they very often occur in an objectless or useless way. 



In its most perfect condition, the nervous system thus consists of two 

 Nature of men- separate mechanisms, the automatic and the influential, and 

 tai emotions, these are so related that they can mutually act on one an- 

 other. The will can exert a control over the so-called reflecting func- 

 tion of the automatic part, and external impressions which have been 

 received by that part can exert a reaction upon the wilL It is in this 

 way that mental emotions may be explained, the power of external influ- 

 ences which antagonize or even overcome the will. 



