OF MUSCULAR MOTION. 193 



307. From this circumstance, the muscles in general 

 are divided into hollow and solid. The former, as we 

 have seen, not directly subject to the will, belong more 

 to the vital and natural functions and are consequently 

 not to be considered at present, while we are speaking 

 of the voluntary muscles, which belong to the order of 

 animal functions. 



308. Among the latter, also, there is much variety. 

 For, not to allude to difference of size, there is great 

 diversity in the disposition of their bands and fasciculi, 

 the direction of their fibres, the proportion of the 

 fleshy to the tendinous part, their course, mode of 

 insertion, &c. 



309. The greatest number are long, and their fleshy 

 bellies terminate at each extremity in tendinous chords, 

 inert, and destitute of irritability, and fixed to the 

 bones, which they move in the manner of levers. 



310. While a very few muscles are destitute of ten- 

 dons, such as the latissimus colli, an equally small 

 number are not inserted into bones, such are the cre- 

 master, as we generally find it, the azygos uvulae, 

 most of the muscles of the eye, &c. 



311. The muscles endowed with those common 

 (298 sq.) and peculiar (306 sq.) powers, are thus pre- 

 pared to perform their actions, which also may be 

 divided into common and peculiar. 



312. A property common to all muscles, and the im- 

 mediate consequence of their irritability, is to become 

 shorter, more rigid, and generally unequal, and, as it 

 were, angular, during contraction. 



To attempt, with J. and D. Bernouilli and other 

 mathematical physicians, to reduce this diminution 

 to, a general admeasurement, is rendered impassible, 



o 



