222 CATENATION OF MOTIONS SECT. XVII' i; 



begin this difquifition early enough for this purpofe, 

 as the catenations of motion feem to begin with 

 life, and are only extinguifhable with it. We have 

 fpoken of the power of irritation, of fenfation, of 

 volition, and of aflbciation, as preceding the fibrous 

 motions ; we now ftep forwards, and confider, that 

 converfely they are in their turn preceded by thofe 

 motions ; and that all the fucceffive trains or cir- 

 cles of our actions are compofed of this twofold 

 concatenation. Thofe we fhall call trains of ac- 

 tion which continue to proceed without any flared 

 repetitions ; and thofe circles of a&ion, when the 

 parts of them return at certain periods, though the 

 trains of which they confift, are not exaclly fimi- 

 Jar. 'The reading an epic poem is a train of ac- 

 tions ; the reading a fong with a chorus at equal 

 diftances in the meafure conflitutes fo many circles 

 of action. 



2. Some catenations of animal motion are pro- 

 duced by reiterated fucceffive irritations, as when 

 we learn to repeat the alphabet in its order by fre- 

 quently reading the letters of it. Thus the vermi- 

 cular motions of the bowels were originally pro- 

 duced by the fucceffive irritations of the paffing 

 aliment ; and the fucceflion of actions of the auri- 

 cles and ventricles of the heart was originally form- 

 ed by fucceffive flimulus of the blood, thefe after- 

 wards become part of the diurnal circles of animal 

 actions, as appears by the periodical returns of 

 hunger, and the quickened pulfe of weak people in 

 the evening. 



Other catenations of animal motion are gradually 

 acquired by fucceffive agreeable fenfations, as in 

 learning a favourite fong or dance ; others by dif- 

 agreeable fenfations, as in coughing or ni&itation ; 

 thefe become aflbciated by frequent repetition, and 

 afterwards compofe parts of greater circles, of ac- 

 tion like thofe above mentioned. 



Other 



