MUSCULAR POWER. 135 



that a different direction may, by their means, 

 be given to the moving power, without altering 

 its position. Many instances occur of their 

 application in this manner, by their being made 

 to pass round corners of bones, and along 

 grooves, or channels, expressly formed for their 

 transmission, and producing the effect of pullies. 



In a great number of muscles, the fibres, 

 instead of running parallel to one another, are 

 made either to converge, or to diverge, in order 

 to suit particular kinds of movements : and we 

 frequently find that different portions of the 

 same muscle have the power of contracting 

 independently of the rest, so as to be capable of 

 producing very various effects, according as they 

 act separately or in combination. This is exem- 

 plified in the muscle of the back, called the 

 Trapezius, represented in Fig. 44. In many 

 instances, the fibres radiate in all directions 

 from a common centre : this is the case with 

 the delicate muscle of the ear-drum, as shown in 

 Fig. 45. In that of the elephant, which is about 

 an inch and a half in diameter, these radiating 

 fibres are very conspicuous, even to the naked 

 eye : and they are also visible in the membrane 

 of the human ear, when viewed with a good 

 microscope.* 



At other times, the muscular fibres run in a 



* Home Phil. Trans, for 1800, p. 1. 



