86 NATURAL THEOLOGY. 



of course, the laws belonging to that substance, 

 and which regulate its action, are unknown to us. 

 We see nothing similar to this contraction in any 

 machine which we can make, or any process 

 which we can execute. So far (it is confessed) 

 we are in ignorance, but no farther. This power 

 and principle, from whatever cause it proceeds, 

 being assumed, the collocation of the fibres to re- 

 ceive the principle, the disposition of the muscles 

 for the use and application of the power, is me- 

 chanical ; and is as intelligible as the adjustment 

 of the wires and strings by which a puppet is 

 moved. We see, therefore, as far as respects the 

 subject before us, what is not mechanical in the 

 animal frame, and what is. The nervous influence, 

 (for we are often obliged to give names to things 

 which we know little about.) — I say the nervous 

 influence, by which the belly or middle of the 

 muscle is swelled, is not mechanical. The utility 

 of the eflfect we perceive — the means, or the pre- 

 paration of means, by which it is produced, we 

 do not. But obscurity as to the origin of muscu- 

 lar motion brings no doubtfulness into our obser- 

 vations, upon the sequel of the process : which 

 observations relate — 1st, to the constitution of 

 the muscle, in consequence of which constitution, 

 the swelling of the belly or middle part is neces- 

 sarily and mechanically followed by a contraction 

 of the tendons; 2dly, to the number and variety 

 of the muscles, and the corresponding number and 

 variety of useful powers which they supply to the 



