428 



ANNUAL register; 1794. 



respect similar^ aud does not include 

 ihe connection of cause and effect. 

 All the definitions of this section 

 are afterward more particularly ex- 

 j^'.ained. 



The business of the 3c/ section is 

 to shew, by experiment, that the 

 organs of sense possess a power of 

 motion, and that these motions con- 

 stitute our ideas ; also that ideas of 

 the imagination consist in a renewal 

 of these motions. The first experi- 

 ments adduced tp this purpose re- 

 late to optical spectra. One of the 

 assertions most worthy of accurate 

 investigation in this section is, that 

 when an organ of sense is totally 

 destroyed, the ideas which werp 

 received by that organ perish with 

 it. This, indeed, ought to follow 

 from the waiter's hypothesis, and he 

 gives some instances of the fact : 

 but we are scarcely prepared to re- 

 ceive it as a general truth. 



S. 4. jays down the laws of an'i- 

 wal c(iusatio7i, afterward to be ex- 

 emplified. 



S. 5. enumerates the four facul- 

 ties or motions of the sensorlum, ir- 

 ritation, sensation, volition, and 

 association. They are thus delined: 

 Irritation is an exertion or change 

 of some extrenie part of the senso- 

 rium residing in the muscles or or- 

 gans of sense, in consequence of the 

 sppulses of external bodies. Sensu- 

 iioii is an exertion or change of the 

 central parts of the sensorium, or of 

 ihe whole of it, hglTinlng at some 

 of the extreme parts. Folitioii is 

 an exertion or change of the central 

 parts, terminating in the extreme 

 parts. Association is an exertion or 

 change of some rxtreme part of the 

 sensorium, in consequence of some 

 antecedent or attendant fibrous con- 

 tractions. The above faculties are 

 nho caWed sensorial' motion's. 



S. 6 .descubtsf our classes cffhrouf 

 viotions, which are contractions of 

 the fibrous parts, correspondent with 

 and caused by the four sensorial mo- 

 tions above-mentioned. They are 

 in consequence denominated irrita- 

 tive, sensitive, voluntary, 3nd fissocir 

 ate, fibrous motions. 



S. 7- treats of irritative motions, 

 noticing the different modes in 

 which they are excited, the modifi- 

 cations that they undergo, and thfi 

 association of other motions with 

 those brought on by the primary ir- 

 ritation. It is also observed that ir- 

 ritative ideas often exist without 

 our attention to them ; as wiaep, 

 though lost in thought, we avoid a 

 tree or bench thiit stajids in the way 

 of our walls. 



S. 8. concerning sensitive jnotuin^, 

 observes that they were originally 

 excited h)' irritatio|i, are occasionally 

 obedient tp volition, and lia^e other 

 motions associated with tjiem. 



5. 9. on voluntary motions, states 

 them to have been originally excited 

 bv irritations. Ideas of recollection 

 are a class of these voluntary mo- 

 tions on which reason, or the act of 

 comparing different ideas, depends. 

 Voluntary motions are occasionally 

 causable \>y sensations, made obe- 

 dient t-.o irritation^, and associated 

 with other motions. 



S. 10. is on associate motions. 

 Muscular, sensitive, and voluntary 

 motions and ideas, excited in traiVis 

 or tribes, become associated, aijd 

 have ever after a tendency to arise 

 simultaneously, or in succession. 



Some additlonalolservations on tfia- 

 sensorial poivers, in sect. 11. relate 

 to the various kinds of stimulation, 

 as adapted to different parts ; to 

 sensation' and volition, desire and 

 aversion, voluntary actions and as- 

 sociations. It is asserted that the 



activity 



