SECT. XVII. i. i. CATENATION, &c, 143 



SECT. XVII. 



THE CATENATION OF MOTIONS. 



I. I. Catenations of animal motion* 2. Are produced by irritations, 

 by fenfation s ^ by 'volitions. 3. They continue fometime after they 

 have been excited Caufe of catenation. 4. We can then exert 

 our attention on other objects. 5. Many catenations of motions go 

 on together. 6. Some links of the catenations of motions may be 

 left without dif uniting the chain. 7. Interrupted circles of mo- 

 tion continue confufedly till they come to the part oj the circle ^ 

 where they were dijlurbed. 8 Weaker catenations are diffever- 

 ed byftronger. 9. Then new catenations take place. 10. Much 

 effort prevents their re-uniting. Impediment of fpeech. 1 1, Trains 

 more enfily dijjevered than circles. 12. Sleep dejlroys volition and 

 external Jlimulus. II. Inftances of various catenations in a young 

 lady playing on a harpfichord. Ill I. What catenations are 

 theftrongeft. 2. Irritations joined with ajffbciations form Jlrong- 

 eft connexions. Vital motions. 3. New links with increafed 

 jorce y cold Jits of ftver produced. 4. New links with decreafed 

 force. Co id bath 5. Irritation joined with fenfation. Inflam- 

 matory fever. Why children cannot tickle themf elves. 6. Voli- 

 tion joined with fenfation. Irritative ideas of found be come f*nfi- 

 ble. 7. Ideas of imagination dijjevered by irritations^ by volition^ 

 production offurprife. 



1. i. To inveftigate with precifion the catenations of animal 

 motions, it would be well to attend to the manner of their pro- 

 duction ; but we cannot 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 aflbcia- 

 tion, as preceding the fibrous motions ; we now ftep forwards, 

 and confider, that converleiy they are in their turn preceded by 

 thofe motions ; and that all the fucceffive trains or circles of our 

 adUons are compoied of this twofold concatenation. Thofe we 

 (hall call trains of alion, which continue to proceed without 

 any dated repetitions ; and thofe circles of action, when the 

 parts of them return at certain periods, though the trains, of 

 which they confift, are not exactly fimilar. The reading an 

 epic poem is a train of actions ; the reading a fong with a cho- 

 rus at equal diftances in the meafure conftitutes fo many circles 

 of action. 



2. Some catenations of animal motion are produced by reiter- 



ated 



