( H8 ) 



thofe I had feen in the component flefliy Fibres of other animals, 

 I caufed a portion of one of them to be drawn, as fecn through 

 the microfcope : this is rcprefented sit Jig. 5, A B C D. The hke 

 folds or wrinkles I afterwards met with in the Fibres compofing 

 the fmall mufcles in a lamb, taken out of the belly, near the 

 hind leg. 



Thefe folds or wrinkles in the flefliy Fibres, not only convince mc 

 what is the reafon why our limbs aflumc a bent pofture when the 

 mufcles are at reft, but we may from hence certainly learn the 

 reafon why we can remain longer fitting than in a ftanding pof- 

 ture, and why, when fitting, we do not keep our arms and hands 

 fully extended or hanging down, but are always moving them 

 about ; for if they remained long in a ftate of reft, one mufcle 

 would be too much extended, and another too much contrad:ed, 

 which would be repugnant to the natural difpofition of the muf- 

 cles. For the fume reafons, when we ftand for any length of time, 

 we do not remain fupported on both feet, but firft raife up one 

 foot and then the other, fo that the fore-part of one foot at a 

 time touches the ground, and then the mufcles of that foot are 

 at reft. 



I was at firft at a lofs to conceive the reafon wliy fome of the 

 circular folds or wrinkles in the Fibres of flcfti and fifli, as in the 

 figure E F G H and I K LM, they are reprefcnted ; but when we 

 recollect, that thefc Fibres arc not round, becaufe they lie clofely 

 comprefled together, then if we fuppofe one of thole Fibres fepa- 

 rated from the adjoining ones to be round, or in a fliort time to 

 aflume a round figure, we may eafily conceive how this comes to 

 pafs : becaufe a flefhy Fibre is compofed almoft one third part of 

 a watery fubftance, which being foon evaporated, the internal part 

 may be wrinkled or contracted in a bent or irregular form. Let 

 us fuppofe J?^. 6, ABODE, to rcprefent a flelhy Fibre, wliich 

 feparated from other Fibres, will be of a round figure, which by 

 the evaporation of it-s moiftuic may lofe its round lliape and . be 



