100 



tkpendently of the object : for whether the organ re- 

 ceives its motion from intestine causes, or from tM ob- 

 ject, the effect is the same with regard to the soul, and 

 perception is instantly present to her. 



Experience proves, that if any series of perceptions 

 whatever affects the brain for a certain time, it thereby 

 contracts a habit of re-producing it in the same order. 

 It is likewise certain, that this habit appertains to the 

 brain, and not to the soul : a burning fever, a ray of 

 the sun, or a violent commotion may destroy it, and 

 such causes influence only the machine. 



All perceptions derive their origin from the senses, 

 and the senses transmit to the seat of the soul the im- 

 pressions they receivt from objects. But objects act 

 on the organ by impulsion only : they impress then 

 certain motions on the sensible fibres* So that a per- 

 ception, or a certain series of perceptions, are connected 

 with one or divers motions which operate successively 

 on different fibres. 



And since the reiteration of the same motions, on the 

 same fibres, effects in them an habitual disposition to 

 produce them afresh in a constant order, we may infer 

 from thence that the sensible fibres are so constructed 

 as to produce in them changes or determinations more 

 or .ess durable, which constitute the precious ground- 

 work of the memory aLd imagination. 



But the sensible fibres are nourished like all the other 

 parts of the body : they assimilate or incorporate with 

 themselves alimentary matter: they grow, and whilst 

 they receive nour>!irnent, they continue to perform their 

 proper functions. So that nutrition conduces to pre- 

 serve to the fibres these determinations, and causes them 

 to take root there ; for as the fibres increase, they ac- 

 quire a gj eater degree of consistence. We may hence 

 discover the crigin of custom, that powerful queen of 

 the s^nsi.;le an iiiiti-i^cnt world. The memory, by 

 ..preM recalling to the -soul the signs of per- 



<:*-. , by assuring .er of the identity ot the percep- 

 tions recalled; t a.d of those which have already alfccted 



